monensin and Poultry-Diseases

In July 1971, the polyether ionophorous antibiotic monensin was introduced in the United States for the control of coccidiosis in poultry. At that time, prospects for new anticoccidial agents were not good. Amprolium had enjoyed several years of use, but many other compounds had been abandoned as resistance to them developed. After the introduction of monensin, most commercial broilers were medicated with the drug and it is still widely used for this purpose today. Apart from in poultry, monensin is also used to control coccidiosis in game birds, sheep, and cattle. Indeed, more animals have been medicated with ionophores, such as monensin, for control of disease than any other medicinal agents in the history of veterinary medicine. In this review, we discuss the discovery, mode of action, and efficacy of monensin, together with matters of importance to the poultry industry such as commercial use, drug resistance, toxicity, pharmacology and residues, host immunity to coccidiosis, and effects in other avian species.

Topics: Animals; Coccidiosis; Coccidiostats; Drug Resistance; Monensin; Poultry; Poultry Diseases

Hygiene, management, chemotherapy and immunity all play a part in the control of coccidiosis. Under the conditions of modern intensive poultry rearing, special reliance is placed upon chemotherapy and since the introduction of the sulphonamides in 1939 a sequence of different types of drugs has been developed. At present the field is dominated by the ionophore antibiotics which have a special mode of action against the extracellular phases of the parasitic life cycle. Drug resistance is a continuing problem which has limited the effective life of most types of drug, although it has been most significant for particular compounds. So far it has not severely affected the efficacy of the ionophores. Immunity is involved in effective prophylaxis and the strong protective immunity which is a feature of most coccidial infections offers promise of a vaccination system. However, much more research will be necessary to bring this promise to fruition. Studies on immune mechanisms, antigenicity, biochemistry and in vitro cultivation may all contribute to the development of methods for controlling a series of infections which are an important obstacle to the development of modern husbandry methods.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Disinfection; Drug Resistance, Microbial; Eimeria; Forecasting; Monensin; Poultry Diseases; Vaccination

Topics: Acriflavine; Animal Feed; Animals; Coccidia; Coccidiosis; Coccidiostats; Drug Combinations; Drug Resistance, Microbial; Eimeria; Genetic Markers; Ionophores; Lasalocid; Monensin; Poultry; Poultry Diseases

New anticoccidials continue to be introduced to the poultry industry on an average of about one every 2 years. Revised requirements have increased costs of discovery, development, and approval by the Food and Drug Administration to several million dollars for each product. Gross sales of anticoccidials are now estimated to be in excess of $30,000,000 annually. Anticoccidials are almost universally used in starter rations for meat-type birds being raised under floor-pen management. Protection is more important with these fast-growing birds than with egg-producing types where immunity and cage layer management modify demands for anticoccidials. Coccidiosis mortality has generally been eliminated by all 25 approved anticoccidials if properly used. Selection of specific anticoccidials is based on the ability of the anticoccidial to: (1) improve weights and (2) feed conversion, and (3) to suppress development of lesions. Costs of the product may influence decisions on which one to use. With some anticoccidials the rapid emergence of drug resistant strains has been the biggest problem. "Switching" among the 13 classes of anticoccidials and the so-called "shuttle program" are common methods used to avoid development of resistance. Preventive medication will probably continue to constitute the major method of coccidiosis control with meat-type poultry if attempts to develop economic cage-type management do not supplant current litter and floor-pen management. Immunity acquired through incidental or planned immunization is more important in control of coccidiosis with layer and breeder flocks raised in floor-pens. Some progress in development of avirulent immunogenic strains of different species of coccidia has been reported and further research efforts in this direction should be encouraged.

Topics: Administration, Oral; Animal Feed; Animals; Antiprotozoal Agents; Chickens; Coccidiosis; Costs and Cost Analysis; Drug Resistance; Eimeria; Immunization; Monensin; Poultry Diseases; Robenidine; Time Factors; United States; United States Food and Drug Administration

Two experiments were conducted to evaluate the effects of dietary sophorolipids (SLs) supplementation as antibiotic alternatives on growth performance and gut health of chickens infected with Eimeria maxima. In experiment 1, 336 (zero-day-old) male broilers were used. The chickens were weighed and randomly allocated to the following 6 treatments groups with 7 chickens/cage and 8 cages/treatment: control group that received a basal diet (NC), positive control group that received a basal diet and was challenged with E. maxima (PC), PC+C18:1 lactonic diacetyled SL (SL1), PC+C18:1 deacetyled SL (SL2), PC+C18:1 monoacetyled SL (SL3), and PC+C18:1 diacetyled SL (SL4). Each SL (200 mg/kg feed) was added to the corresponding treatment group. In experiment 2, 588 (zero-day-old) male broilers were used. The chickens were randomly allocated to the following experimental groups with 10 or 11 chickens/cage and 8 cages/treatment: NC, PC, PC+ monensin at 90 mg/kg feed (MO), PC+SL1 at 200 mg/kg feed (SL1 200), PC+SL1 at 500 mg/kg feed (SL1 500), PC+SL4 at 200 mg/kg feed (SL4 200), and PC+SL4 at 500 mg/kg of feed (SL4 500). The chickens and feed were weighed at 0, 7, 14, 20, and 22 d to determine growth performance. In both experiments, all chickens except the NC group were orally infected with E. maxima (10,000 oocysts/chicken) at d 14. One chicken per cage was euthanized at d 20 to sample jejunal tissue to measure lesion scores, cytokines, and tight junction (TJ) proteins. Excreta samples were collected daily between d 20 and 22 to measure oocyst numbers. Data were analyzed using Mixed Model (PROC MIXED) in SAS. In experiment 1, SLs did not affect the growth of broiler chickens, but SL4 decreased (P < 0.05) the lesion score and oocyst number compared to PC chickens. In terms of cytokines and TJ protein gene expression, SLs increased (P < 0.05) IL-1β, IL-6, IL-17F, IL-4, IL-13, occludin, and ZO1 levels compared to PC chickens. In experiment 2, monensin increased (P < 0.05) body weight, and decreased (P < 0.05) the lesion score and oocyst number compared to the PC group. SL4 500 increased (P < 0.05) average daily gain and feed conversion ratio but decreased (P < 0.05) lesion score and fecal oocyst number. SL4 decreased (P < 0.05) IL-6, IL-17F, TNFSF-15, IL-2, and IL-10 levels but increased (P < 0.05) occludin and ZO-1 levels. Overall, dietary SL supplementation, especially SL4, improved growth and gastrointestinal functionality of young broiler chickens, demonstrating sig

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Chickens; Coccidiosis; Diet; Dietary Supplements; Eimeria; Interleukin-17; Interleukin-6; Intestines; Male; Monensin; Occludin; Oleic Acids; Oocysts; Poultry Diseases

Coccidiosis is the most important parasitic disease of the poultry production industry. Due to increasing resistance to conventional anticoccidial agents, it is necessary to find new anticoccidial compounds. Herbal compounds such as those from Artemisia species are promising weapons in this regard since preliminary studies have shown its anticoccidial effects. To compare the anticoccidial effect of a granulated extract of Artemisia sieberi (GEAS) versus monensin in experimental broiler coccidiosis, 120 one-day old Ross 308 broiler chickens were divided in four groups, each with three replicates (n=10). Group 1 was separated as an uninfected negative control and received no treatment. At 21days of age, groups 2, 3 and 4 were inoculated with a mixed suspension of 2×10(5) oocysts of Eimeria tenella, Eimeria maxima, Eimeria acervulina and Eimeria necatrix. Group 2 was maintained as an infected positive control and received no treatment while groups 3 and 4 received GEAS (5mg/kg feed), and monensin (110mg/kg feed) from the first day until 42days of age as a feed additive, respectively. Five days after inoculation, the number of oocycts per gram (OPG) of feces for 7 successive days was measured. Also, mean body weight (MBW), weight gain (WG), feed intake (FI) and feed conversion ratio (FCR) were determined weekly in all groups and replicates. The results showed that GEAS and monensin improved performance attributes (FI, MBW, WG, FCR) and significantly (P<0.05) decreased OPG in inoculated broiler chickens.

Topics: Animals; Artemisia; Body Weight; Chickens; Coccidiosis; Coccidiostats; Eating; Feces; Monensin; Oocysts; Parasite Egg Count; Plant Extracts; Poultry Diseases

1. A herbal extract containing a blend of three essential oils, derived from oregano, laurel leaf and lavender, was investigated as a feed additive alternative to the conventional anticoccidial sodium monensin. 2. Broilers were infected with a mixture of Eimeria species or left uninfected. Both infected and uninfected broilers were provided with diets containing either herbal extract (HEX), monensin (MON) or without these supplements (CON). The HEX group had 50 mg herbal extract/kg diet and the MON group 100 mg monensin/kg diet. 3. All of the uninfected broilers exhibited higher body weight gain and better feed conversion when compared with their infected counterparts at d 28 and 42 of age. Both HEX and MON supplements caused significant improvements in performance in the infected broilers, but failed to have any effect on uninfected broilers. 4. Faecal oocyst output measured daily by sampling excreta, and expressed on a per bird basis, was lower in the HEX and MON groups than in the CON group. However, the herbal extract was not as effective as monensin in reducing oocyst excretion. Coccidial infection caused a significant increase in total intestinal length and caecal weight, but the dietary treatments did not influence these measurements. 5. These results indicate that providing a herbal extract in the diet was not as effective as monensin in protecting broilers exposed to a coccidial challenge.

Topics: Animal Feed; Animals; Chickens; Coccidiosis; Coccidiostats; Coinfection; Dietary Supplements; Eimeria; Feces; Female; Laurus; Lavandula; Male; Monensin; Oils, Volatile; Oocysts; Origanum; Plant Oils; Poultry Diseases

Aflatoxins (AF) are a major problem in broiler production and are significant economic and public health burdens worldwide. A commercial sodium bentonite (Na-B) adsorbent was used to prevent the effect of AF [50 µg of aflatoxin B₁ (AFB₁)/kg of feed] in broiler productivity, biochemical parameters, macroscopic and microscopic liver changes, and AFB₁ liver residues. The influence of Na-B (0.3%) and monensin (MON, 100 mg/kg), alone or in combination, was investigated in depth. The dietary treatments were as follows: treatment (T) 1: basal diet (B); T2: B + MON; T3: B + Na-B; T4: B + Na-B + MON; T5: B + AFB₁; T6: B + AFB₁ + Na-B + MON; T7: B + AFB₁ + MON; T8: B + AFB₁ + Na-B. Birds were fed dietary treatments for 28 d (d 18 to 46). No significant differences (P < 0.05) were observed among treatments with respect to broiler performance, biochemical parameters, or relative liver weights. With the exception of T8, all livers showed histopathological alterations, with accumulation of fat vacuoles. The normal appearance of livers from T8 showed the protective effect of Na-B against aflatoxicosis. The residual AFB₁ levels in livers from T5 to T8 ranged from 0.2 to 1.0 ng/g and were higher in livers from T6 (P < 0.05). Results of this study indicate a competition between AFB₁ and MON for adsorption sites on Na-B when feed contains low levels of the toxin, indicating a nonselective adsorption capacity of this particular Na-B. In addition, significant levels of AFB₁ in livers indicate that this determination is an important technique not only for diagnosis of aflatoxicosis in broilers, but also for quality control of avian products.

Topics: Adsorption; Aflatoxin B1; Animal Feed; Animals; Antidotes; Antiprotozoal Agents; Bentonite; Chickens; Diet; Dose-Response Relationship, Drug; Liver; Male; Monensin; Poultry Diseases

A method previously described by Jeffers and Bentley, involving calculation of a growth and survival ratio and optimal anticoccidial activity index, was used to investigate the sensitivity of 23 field isolates of Eimeria obtained from turkey flocks to the ionophorous antibiotic monensin. Isolates were obtained from litter and intestinal samples from several major turkey-growing regions of the United States, and in most cases contained at least two species of Eimeria. A mixture of strains that had been maintained in the laboratory for many years in the absence of exposure to anticoccidial drugs was found to be sensitive to monensin. Six of the field isolates were judged sensitive, seven partially resistant, and ten resistant to the drug, judged by the Jeffers and Bentley criteria. This is the first report of the acquisition of resistance to monensin in isolates of Eimeria from turkey flocks in the United States.

Topics: Animals; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria; Female; Monensin; Poultry Diseases; Turkeys

Anticoccidial vaccine and an anticoccidial drug rotation program were compared to determine which program was more effective in producing coccidia populations sensitive of 1 ppm diclazuril. The study used an anticoccidial drug-sensitivity battery test (AST) to determine the baseline level of diclazuril sensitivity to field isolates of Eimeria spp. from seven broiler complexes that had used diclazuril. Based on percentage reduction in weight gain and lesion scores, 25% or fewer of the isolates were effectively controlled by diclazuril. Following the baseline sampling, four of the complexes switched to a nondiclazuril in-feed anticoccidial drug program and three of the complexes switched to a vaccination program for two broiler grow-out cycles as the sole coccidiosis-control program. This study demonstrated that the vaccine used (Coccivac-B) contained anticoccidial drug-sensitive strains. Eimeria isolates were subsequently collected from the identical houses and diclazuril AST results were compared with the baseline AST results. Following the two grow-out cycles, sensitivity of the isolates to diclazuril from the four complexes that continued to use in-feed anticoccidial drugs remained essentially unchanged. The isolates from the three complexes that switched to the vaccination program demonstrated a marked increase in diclazuril sensitivity, with 60%-100% of the isolates from each complex effectively controlled by diclazuril. Vaccination with the anticoccidial drug-sensitive strains produced a measurable increase in the level of sensitivity to diclazuril.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria; Male; Monensin; Nicarbazin; Nitriles; Poultry Diseases; Protozoan Vaccines; Pyrans; Triazines

Twenty European Eimeria spp. field isolates were subjected to an anticoccidial sensitivity test (AST). The anticoccidial drugs tested were diclazuril (Clinacox) and monensin (Elancoban). The assay was performed in a battery cage trial. Infected medicated birds were compared with an unmedicated control group. Coccidial lesion scores and oocyst shedding were used as parameters. The results of the AST show that resistance is common amongst coccidiosis field isolates, especially Eimeria acervulina (68% and 53% resistance for diclazuril and monensin, respectively). Resistance is less frequent amongst Eimeria maxima (38% and 50% resistance for diclazuril and monensin, respectively) and Eimeria tenella isolates (23% and 38% resistance for diclazuril and monensin, respectively). A highly significant influence of the coccidiosis prevention program (live coccidiosis vaccination with Paracox-5 vs. anticoccidial drugs in feed) on the sensitivity patterns of Eimeria spp. field isolates for both diclazuril (P= 0.000) and monensin (P= 0.001) was found. Further, when looking at the single species and each anticoccidial drug level, significantly more sensitivity of E. acervulina for monensin (P= 0.018), E. maxima for diclazuril (P = 0.009), and E. tenella for diclazuril (P = 0.007) was found in isolates originating from vaccinated flocks. Moreover, for E. acervulina and diclazuril, E. maxima and monensin, and E. tenella and monensin a trend toward higher sensitivity of isolates for these products was found when live coccidiosis vaccination was applied. The present study shows that sensitivity for the anticoccidial drugs diclazuril and monensin is more frequent in Eimeria spp. field isolates originating from broiler farms where a coccidiosis vaccination policy is followed.

Topics: Agriculture; Animals; Chickens; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria; Monensin; Nitriles; Poultry Diseases; Protozoan Vaccines; Triazines

A 42-d floor pen study was conducted with broiler chickens comparing the effects on bird performance of 12 ppm TAMUS 2032 (also known as BT) and 55 ppm bacitracin methylene disalicyclate (BMD) when fed alone or in combination with 99 ppm monensin (MON). Unmedicated and 99 ppm MON treatments were included in the study design. Beginning on d 22 of study, birds in all 6 treatments were subjected to a modulated house temperature and airflow to mimic conditions conducive to outbreaks of colibacillosis. A natural outbreak of colibacillosis developed beginning on d 27. Primary lesions in dead birds included airsacculitis and pericarditis with occasional findings of perihepatitis. At d 42 of study, means for weight gain in the TAMUS 2032 and TAMUS 2032 + MON treatments were greater in comparison with the unmedicated and BMD treatments, and means for feed conversion for both treatments were improved in comparison with the unmedicated treatment. Mean feed conversion in the TAMUS 2032 + MON treatment was also improved in comparison with BMD treatment. Mortality due to colibacillosis was reduced in the TAMUS 2032 (0.051%), TAMUS 2032 + MON (0.642%), and MON + BMD (1.515%) treatments in comparison with the unmedicated treatment (13.402%) and the BMD treatment (11.159%). The results of improved performance and reduced mortality indicated that 12 ppm TAMUS 2032 was highly efficacious against colibacillosis in growing chickens. The reduced mortality percentages in the MON + BMD treatment indicated that this combination also provided a good level of protection against the natural outbreak of colibacillosis.

Topics: Animals; Bacitracin; Chickens; Disease Outbreaks; Drug Therapy, Combination; Escherichia coli Infections; Female; Hepatitis, Animal; Hot Temperature; Housing, Animal; Male; Monensin; Oligopeptides; Pericarditis; Poultry Diseases; Salicylates; Ventilation

Three experiments (Exp.) were conducted to determine the interactive effects of sodium bentonite (NaB) with the efficacy of monensin (MON) or salinomycin (SAL) in coccidiosis-infected chicks. Male broiler chicks 5 to 14 d of age were used, and each treatment was replicated with eight (Exp. 1) or four (Exp. 2 and 3) pens of five chicks each. In Exp. 1, MON (80 ppm), NaB (0.50%), or MON+NaB were fed to uninfected and coccidiosis-infected (5 x 10(5) sporulated Eimeria acervulina oocysts on Day 2 of the Exp.) chicks in a 2 x 2 x 2 factorial arrangement of treatments. Experiment 2 was identical to Exp. 1, but SAL (30 ppm) replaced MON as the anticoccidial additive. In Exp. 3, MON (55 ppm) or SAL (22 ppm) were added individually or with NaB (0.50%) to diets for uninfected or coccidiosis-infected chicks. Coccidial infection reduced (P < 0.01) gain, feed intake, gain:feed, plasma carotenoids, and percentage tibia ash in all experiments. The MON and SAL additions increased these response criteria in infected chicks (coccidiosis by anticoccidial, P < 0.07), except MON did not increase (P > 0.10) feed intake or tibia ash in Exp. 3. In Exp. 3, NaB partially reduced the positive effect of MON on daily gain (NaB by MON, P < 0.03), and of SAL on feed intake (NaB by SAL, P < 0.08). The NaB addition also increased gain:feed (P < 0.08), and the increase was greater in infected chicks (coccidiosis by NaB, P < 0.08). Also in Exp. 3, SAL increased feed intake more in chicks not fed NaB than in chicks fed NaB (SAL by NaB, P < 0.08). Dietary NaB (0.5%) may reduce the efficacy of MON and SAL in coccidiosis-infected chicks when these additives are added at less than recommended levels.

Topics: Animals; Bentonite; Carotenoids; Chickens; Coccidiosis; Coccidiostats; Diet; Drug Interactions; Eating; Male; Monensin; Poultry Diseases; Pyrans; Tibia; Weight Gain

Anticoccidial efficacy of a drug combination monensin at 8 p.p.m. plus the new antioxidant duokvin at 120 p.p.m. in the feed was compared with that of monensin alone at the recommended level of 100 p.p.m. against a field isolate of the coccidium Eimeria acervulina Tyzzer, 1929 in a battery study. Both monensin and monensin duokvin combination were effective against E. acervulina when judged by weight gain, feed conversion and faecal scores. There was no significant difference in the chemoprophylactic activity of either treatments. Neither monensin at 100 p.p.m. nor the combination proved effective in terms of oocyst production. In accordance with the earlier findings with E. tenella, the combination seems appropriate for field trials.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Drug Combinations; Eimeria; Feces; Monensin; Poultry Diseases; Quinolines; Weight Gain

A floor pen trial was carried out on broilers in 1975 to compare the anticoccidial efficacy of monensin1), 3,5 dinitro-o-toluamide2), clopidol3), amprolium + ethopabacte4), amprolium + ethopabate + sulfaquinoxaline + pyrimethamine5) and robenidine6) in the presence of untreated controls. 4,200 Hybro chicks were distributed over twenty-eight pens, each initially housing 150 birds. Four pen replicates were allocated to each of the seven treatments. With the exception of robenidine, all agents used resulted in a statistically significant (P less than or equal to 0,05) gain in final weight compared with the untreated controls. The feed conversion rate showed significant (P less than or equal to 0,05) improvement in the groups treated with monensin, robenidine, amprolium + ethopabate.

Topics: Amprolium; Animals; Chickens; Clinical Trials as Topic; Clopidol; Coccidiosis; Coccidiostats; Ethopabate; Monensin; Poultry Diseases; Pyrimethamine; Robenidine; Sulfaquinoxaline

Worldwide distributed coccidiosis is caused by infection of both Eimeria species and Cystoisospora in the host intestine and causes huge economic losses to the livestock industry, especially the poultry industry. The control of such diseases relies mainly on chemoprophylaxis with anticoccidials, which has led to a very common drug resistance in this field. However, the genetic mechanisms underlying resistance to many anticoccidial drugs remain unknown. In this study, strains of E. tenella resistant to 250 mg/kg monensin were generated and characterized. Forward genetic approaches based on pooled genome sequencing, including experimental evolution and linkage group selection, were used to locate candidate targets responsible for resistance to monensin and diclazuril in E. tenella. A total of 16 nonsynonymous mutants in protein-coding genes were identified in monensin-resistant strains, and two genomic regions with strong selection signals were also detected in diclazuril-resistant strains. Our study reveals the genetic characterization of the experimental evolution and linkage group selection in Eimeria species, and also provides important information that contributes to the understanding of the molecular mechanism of drug resistance in coccidia.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Eimeria tenella; Monensin; Poultry Diseases

Coccidiosis is a poultry disease that occurs worldwide and is caused by Eimeria species. The infection is associated with reduced feed efficiency, body weight gain, and egg production. This study aimed to investigate the current status of coccidiosis and anticoccidial resistance to anticoccidial drugs used as part of control strategies for this disease in Korean chicken farms.. An overall prevalence of 75% (291/388) was found. Positive farms contained several Eimeria species (mean = 4.2). Of the positive samples, E. acervulina (98.6%), E. maxima (84.8%), and E. tenella (82.8%) were the most prevalent species. Compared with cage-fed chickens, broilers and native chickens reared in free-range management were more at risk of acquiring an Eimeria infection. Sensitivities to six anticoccidial drugs (clopidol, diclazuril, maduramycin, monensin, salinomycin, and toltrazuril) were tested using nine field samples. Compared with untreated healthy control chickens, the body weight gains of infected chickens and treated/infected chickens were significantly reduced in all groups. Fecal oocyst shedding was significantly reduced in four clopidol-treated/infected groups, three diclazuril-treated/infected groups, two toltrazuril-treated/infected groups, one monensin-treated/infected group, and one salinomycin-treated/infected group, compared with the respective untreated/infected control groups. Intestinal lesion scores were also reduced in three clopidol-treated/infected groups, one monensin-treated/infected group, and one toltrazuril-treated/infected group. However, an overall assessment using the anticoccidial index, percent optimum anticoccidial activity, relative oocyst production, and reduced lesion score index found that all field samples had strong resistance to all tested anticoccidial drugs.. The results of this large-scale epidemiological investigation and anticoccidial sensitivity testing showed a high prevalence of coccidiosis and the presence of severe drug resistant Eimeria species in the field. These findings will be useful for optimizing the control of coccidiosis in the poultry industry.

Topics: Animals; Chickens; Clopidol; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria; Farms; Monensin; Oocysts; Poultry Diseases; Republic of Korea; Weight Gain

A clinical study was made into the abilities of nicarbazin and monensin and a nicarbazin + monensin combination to control

Topics: Animals; Coccidiosis; Coccidiostats; Drug Synergism; Eimeria; Male; Monensin; Nicarbazin; Poultry Diseases

The objective of this study was to evaluate the effect of supplementation with 100ppm sodium monensin or 0.15% of a blend of functional oils (cashew nut oil + castor oil) on the intestinal microbiota of broilers challenged with three different Eimeria spp. The challenge was accomplished by inoculating broiler chicks with sporulated oocysts of Eimeria tenella, Eimeria acervulina, and Eimeria maxima via oral gavage. A total of 864, day-old male broiler chicks (Cobb) were randomly assigned to six treatments (eight pens/treatment; 18 broilers/pen) in a 3 × 2 factorial arrangement, composed of three additives (control, monensin or blend), with or without Eimeria challenge. Intestinal contents was collected at 28 days of age for microbiota analysis by sequencing 16s rRNA in V3 and V4 regions using the Illumina MiSeq platform. Taxonomy was assigned through the SILVA database version 132, using the QIIME 2 software version 2019.1. No treatment effects (p > 0.05) were observed in the microbial richness at the family level estimated by Chao1 and the biodiversity assessed by Simpson's index, except for Shannon's index (p < 0.05). The intestinal microbiota was dominated by members of the order Clostridiales and Lactobacillales, followed by the families Ruminococcaceae, Bacteroidaceae, and Lactobacillaceae, regardless of treatment. When the controls were compared, in the challenged control group there was an increase in Erysipelotrichaceae, Lactobacillaceae, Bacteroidaceae, Streptococcaceae, and Peptostreptococcaceae, and a decrease in Ruminococcaceae. Similar results were found for a challenged group that received monensin, while the blend partially mitigated this variation. Therefore, the blend alleviated the impact of coccidiosis challenge on the microbiome of broilers compared to monensin.

Topics: Anacardium; Animal Feed; Animals; Chickens; Coccidiosis; DNA, Protozoan; Eimeria; Gastrointestinal Microbiome; Male; Monensin; Oocysts; Plant Oils; Poultry Diseases; Ricinus; RNA, Ribosomal, 16S

The aim of the study was to evaluate the effects of a cashew nut shell oil and commercial castor oil blend (CNSL-Castor oil) on the performance and microbiota of broiler chickens with and without coccidiosis challenge. A total of 864 one-day-old male chicks (Cobb) were randomly distributed to receive 6 treatments (8 pens/treatment; 18 chicks/pen) in a 3 × 2 factorial, with 3 additives (control [non-additives], 100 ppm sodium monensin, or 0.15% CNSL-Castor oil blend), and 2 levels of coccidiosis challenge at 14 D of age (unchallenged or inoculated by gavage with 1 mL of solution containing oocysts sporulated with Eimeria tenella, Eimeria acervulina, and Eimeria maxima). No differences in productive performance were observed among treatments in the pre-challenge period and in unchallenged birds (P > 0.05). Seven-days post-challenge, birds receiving monensin performed better than birds in the positive control group (non-additive and challenge) or in the CNSL-Castor oil group (P > 0.05). However, 14 D post-challenge, birds supplemented with CNSL-Castor oil presented higher weight gain and better feed conversion (P > 0.05), without any change in feed intake (P > 0.05). During the accumulated period (1 to 42 D of age), the live weight, weight gain, and feed intake did not differ between the CNSL-Castor oil and monensin groups, both of which presented higher values than the positive control. Lactobacillus spp. and Clostridium perfringens numbers were increased in the challenged birds (P < 0.05). CNSL-Castor oil supplementation reduced Clostridium cluster XIV, C. perfringens, and S. aureus, compared with the monensin and control groups (P > 0.05). In addition, the CNSL-Castor oil group presented the highest number of Lactobacillus spp. copies, followed by the monensin and positive control groups (P > 0.05). Thus, monensin and CNSL-Castor oil effectively minimized the impact of coccidiosis at different times. While monensin acts as an antimicrobial, CNSL-Castor oil modulates the intestinal microbiota with antimicrobial action against gram-positive bacteria, mainly C. perfringens and S. aureus.

Topics: Anacardium; Animal Feed; Animals; Anti-Infective Agents; Castor Oil; Chickens; Coccidiosis; Diet; Dietary Supplements; Eimeria; Gastrointestinal Microbiome; Male; Monensin; Plant Oils; Poultry Diseases; Random Allocation

Polyether ionophores are widely used to treat and control coccidiosis in chickens. Widespread use of anticoccidials resulted in worldwide resistance. Mechanisms of resistance development and expansion are complex and poorly understood. Relative proteomic quantification using LC-MS/MS was used to compare sensitive reference strains (Ref-1, Ref-2) with putatively resistant and moderately sensitive field strains (FS-R, FS-mS) of Eimeria tenella after isotopic labelling with tandem mass tags (TMT). Ninety-seven proteins were identified, and 25 of them were regulated. Actin was significantly upregulated in resistant strains in comparison with their sensitive counterparts. On the other hand, microneme protein (MIC4) was downregulated in resistant strains. Optimization of labelling E. tenella sporozoites by TMT might identify further proteins that play a role in the obvious complex mechanism leading to resistance against Monensin.

Topics: Actins; Animals; Chickens; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria tenella; Ionophores; Monensin; Poultry Diseases; Proteomics; Protozoan Proteins; Sporozoites; Tandem Mass Spectrometry

Essential oil of oregano ( OEO: ) has proven to be a potential candidate for controlling chicken coccidiosis. The aim of the current study is to determine whether OEO and an approved anticoccidial, monensin sodium ( MON: ), as in-feed supplements could create a synergism when combined at low dosages. Day-old broiler chickens were separated into six equal groups with six replicate pens of 36 birds. One of the groups was given a basal diet and served as the control ( CNT: ). The remaining groups received the basal diet supplemented with 100 mg/kg MON, 50 mg/kg MON, 24 mg/kg OEO, 12 mg/kg OEO, or 50 mg/kg MON + 12 mg/kg OEO. All of the chickens were challenged with field-type mixed Eimeria species at 12 d of age. Following the infection (i.e., d 13 to 42), the greatest growth gains and lowest feed conversion ratio values were recorded for the group of birds fed 100 mg/kg MON (P < 0.05), whereas results for the CNT treatment were inferior. Dietary OEO supplementations could not support growth to a level comparable with the MON (100 mg/kg). The MON programs were more efficacious in reducing fecal oocyst numbers compared to CNT and OEO treatments (P < 0.05). Serum malondialdehyde and nitric oxide concentrations were decreased (P < 0.01), whereas superoxide dismutase (P < 0.05) and total antioxidant status (P < 0.01) were increased in response to dietary medication with MON and OEO. All MON and OEO treatments conferred intestinal health benefits to chickens by improving their morphological development and enzymatic activities. The results suggest that OEO supported the intestinal absorptive capacity and antioxidant defense system during Eimeria infection; however, it displayed little direct activity on the reproductive capacity of Eimeria This might be the reason for inferior compensatory growth potential of OEO compared to that MON following the challenge. Combination MON with OEO was not considered to show promise for controlling chicken coccidiosis because of the lack of a synergistic or additive effect.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Drug Therapy, Combination; Eimeria; Female; Male; Monensin; Origanum; Plant Oils; Poultry Diseases

Standard methods of determining the ionophore sensitivity of Eimeria rely on infecting chickens with an isolate or a mixture of Eimeria spp. oocysts in the presence of different anti-coccidial drugs. The purpose of this study was to develop a rapid in vitro method for assessing salinomycin and monensin sensitivity in Eimeria tenella. Cultures of MDBK cells were grown to 85% confluency, and then inoculated with excysted E. tenella laboratory strain (APU-1) sporozoites in the presence of different concentrations of salinomycin or monensin. At various timepoints, the monolayers were fixed for counting intraceullar sporozoites, or were subjected to DNA extraction, followed by molecular analysis using quantitative (qPCR) or semi-quantitative PCR (sqPCR). Preliminary experiments showed that 24h was the optimum time for harvesting the E. tenella-infected cell cultures. The average number of E. tenella sporozoites relative to untreated controls displayed a linear decrease between 0.3 and 33.0 μg/ml salinomycin and between 0.3 and 3.3 μg/ml monensin. A similar pattern was observed in the relative amount of E. tenella DNA as measured by sqPCR. A linear decrease in the relative amount of E. tenella DNA was observed over the entire range of salinomycin and monensin concentrations as measured by qPCR possibly reflecting the greater sensitivity of this assay. Comparison of sporozoite counting, sqPCR, and qPCR signals using a criterion of 50% inhibition in sporozoite numbers or level of PCR amplification product showed good agreement between the three assays. E. tenella field isolates (FS-1 and FS-2) displaying resistance to salinomycin and monensin were evaluated in the in vitro assay using qPCR and sqPCR. Compared to E. tenella APU-1, the E. tenella FS-1 and FS-2 isolates showed higher levels of E. tenella DNA at 24h by both qPCR and sqPCR. This in vitro assay represents a significant advance in developing rapid, cost-effective methods for assessing ionophore sensitivity in E. tenella.

Topics: Animals; Cell Culture Techniques; Chickens; Coccidiosis; Coccidiostats; Costs and Cost Analysis; Eimeria tenella; Ionophores; Monensin; Oocysts; Poultry Diseases; Pyrans; Real-Time Polymerase Chain Reaction; Sporozoites

Clay feed additives have been increasingly incorporated into animal diets to prevent aflatoxicosis. Due to the nonselective nature of the binding interaction, many important components of the diets could also be made unavailable because of these feed additives. The anticoccidial monensin (MON) could also be sequestered by these clays. The use of sodium bentonite (Na-B) from a mine in the province of Mendoza, Argentina, was investigated as a sequestering agent to prevent the effects of 100 µg/kg of dietary aflatoxin B(1) (AFB(1)). In vitro studies demonstrated that the above Na-B was a good candidate to prevent aflatoxicosis. They also showed that MON competes with AFB(1) for the adsorption sites on the clay surface and effectively displaces the toxin when it is in low concentration. Even though the levels of MON in diets, approximately 55 mg/kg, are high enough to not be significantly changed as a consequence of the adsorption, they can further affect the ability of the clays to bind low levels of AFB(1). An in vivo experiment carried out with poultry showed that 100 µg/kg of AFB(1) does not significantly change productive or biochemical parameters. However, liver histopathology not only confirmed the ability of this particular Na-B to prevent aflatoxicosis but also the decrease of this capacity in the presence of 55 mg/kg of MON. This is the first report stressing this fact and further research should be performed to check if this behavior is a characteristic of the assayed Na-B or of this type of clay. On the other hand, the presence of MON should also be taken into account when assaying the potential AFB(1) binding ability of a given bentonite.

Topics: Adsorption; Aflatoxins; Animal Feed; Animals; Antidotes; Bentonite; Chemical and Drug Induced Liver Injury; Chickens; Chronic Disease; Diet; Drug Interactions; Ionophores; Liver; Male; Monensin; Poultry Diseases

A protective digestive microflora helps prevent and reduce broiler infection and colonization by enteropathogens. In the current experiment, broilers fed diets supplemented with probiotics and essential oil (EO) blends were infected with a standard mixed Eimeria spp. to determine effects of performance enhancers on ileal and cecal microbial communities (MCs). Eight treatment groups included four controls (uninfected-unmedicated [UU], unmedicated-infected, the antibiotic BMD plus the ionophore Coban as positive control, and the ionophore as negative control), and four treatments (probiotics BC-30 and Calsporin; and EO, Crina Poultry Plus, and Crina PoultryAF). Day-old broilers were raised to 14 days in floor pens on used litter and then were moved to Petersime batteries and inoculated at 15 days with mixed Eimeria spp. Ileal and cecal samples were collected at 14 days and 7 days postinfection. Digesta DNA was subjected to pyrosequencing for sequencing of individual cecal bacteria and denaturing gradient gel electrophoresis (DGGE) for determination of changes in ileal and cecal MC according to percentage similarity coefficient (%SC). Pyrosequencing is very sensitive detecting shifts in individual bacterial sequences, whereas DGGE is able to detect gross shifts in entire MC. These combined techniques offer versatility toward identifying feed additive and mild Eimeria infection modulation of broiler MC. Pyrosequencing detected 147 bacterial species sequences. Additionally, pyrosequencing revealed the presence of relatively low levels of the potential human enteropathogens Campylobacter sp. and four Shigella spp. as well as the potential poultry pathogen Clostridiun perfringens. Pre- and postinfection changes in ileal (56%SC) and cecal (78.5%SC) DGGE profiles resulted from the coccidia infection and with increased broiler age. Probiotics and EO changed MC from those seen in UU ilea and ceca. Results potentially reflect the performance enhancement above expectations in comparison to broilers not given the probiotics or the specific EO blends as feed supplements.

Topics: Animal Feed; Animals; Bacteria; Biodiversity; Cecum; Chickens; Coccidiosis; Coinfection; Denaturing Gradient Gel Electrophoresis; DNA, Bacterial; DNA, Ribosomal; Eimeria; Ileum; Male; Monensin; Oils, Volatile; Poultry Diseases; Probiotics; Proton Ionophores; Random Allocation; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Weight Gain

1. This study investigated the effect of Eimeria spp./Clostridium perfringens induced necrotic enteritis and traditional antibiotic preventatives on intestinal micro-architecture and mucin profile. 2. A total of 600 Cobb 500 broiler chickens were randomly assigned to the following three groups: (i) unchallenged, (ii) challenged, and (iii) zinc bacitracin/monensin (ZnB/monensin) (n = 25 chickens/pen, 8 pens/group). The challenged and ZnB/monensin chickens were individually inoculated with Eimeria acervulina, E. maxima and E. tenella and C. perfringens type A (EHE-NE18) at 9 and 15 d post-hatch respectively, to induce necrotic enteritis. 3. The challenge procedure significantly decreased villus height, increased villus width and increased crypt depth in the challenged compared to the unchallenged chickens. Zinc bacitracin and monensin maintained villus-crypt structure similar to that of the unchallenged chickens. 4. Mucin profile was not affected by Eimeria spp./C. perfringens challenge as demonstrated by periodic acid-Schiff and high iron diamine-alcian blue pH 2 x 5 staining. Zinc bacitracin and monensin decreased the number of intestinal mucin-containing goblet cells. 5. Lectin histochemistry showed a trend towards greater Arachis hypogea (PNA) reactivity in unchallenged chickens. 6. In summary, Eimeria spp./C. perfringens challenge disrupted intestinal micro-architecture; however, challenge did not appear to affect intestinal mucin profile. Traditional antibiotics, zinc bacitracin and monensin maintained micro-architecture.

Topics: Animals; Anti-Bacterial Agents; Bacitracin; Chickens; Clostridium Infections; Clostridium perfringens; Coccidiosis; Coccidiostats; Eimeria; Enteritis; Goblet Cells; Intestinal Diseases; Intestines; Lectins; Monensin; Mucins; Necrosis; Poultry Diseases; Random Allocation; South Australia; Species Specificity

Peracute onset of disease was reported in a 42-wk-old broiler breeder flock that was presented by error with feed containing monensin at approximately seven times the approved level for broiler chickens. Morbidity and mortality were extremely high, and the affected chickens displayed feed refusal, decreased water consumption, and severe paralysis that ranged from abnormal gait to a complete inability to move. During the first 10 days postingestion of the suspect feed, mortality in hens reached 13.7% and 70.9% in the roosters. Hen day production decreased from 67% to 3% in the same period of time. A total of 638 g/ton of monensin was detected in suspect feed samples by one laboratory and 740 g/ton in a second laboratory. Twenty-one days after removal of the suspect feed, the mortality rate returned to normal levels in both hens and roosters, albeit feed consumption and egg production remained extremely low, which prompted the company involved to eliminate the flock.

Topics: Animal Feed; Animals; Chickens; Dehydration; Female; Male; Monensin; Muscle, Skeletal; Myocardium; Oviposition; Paralysis; Poultry Diseases; Streptomyces; United States

Monensin and vitamin E concentrations, as well as histopathology of skeletal muscles and myocardium, were evaluated in broad-breasted white turkeys kept in commercial facilities. Turkeys with knockdown syndrome had myopathy of skeletal muscles, but no lesions in the myocardium. Generally, concentration of monensin in serum was highest in turkeys diagnosed with knockdown syndrome given more than 90 mg/kg of monensin in the diet, followed by turkeys diagnosed with knockdown syndrome given <90 mg/kg of monensin in the diet, healthy turkeys fed a diet that contained <90 mg/kg of monensin, and finally healthy turkeys fed a diet free of monensin (not detectable). However, the concentration of monensin was highly variable within each group, and the median was lower than the average. Vitamin E concentrations in the livers varied from low-normal to below normal and were statistically higher in healthy turkeys fed a diet free of monensin than in the livers of birds from the 3 groups exposed to monensin. This suggests that the concentration of monensin in serum positively correlates to the severity of clinical signs and pathology and to the amount of monensin in the feed. Although the methodology developed to detect serum monensin concentrations is beneficial and accurate for case investigations, it is recommended that several samples from each flock be evaluated because of variation within a flock. The current study also suggests that monensin in the feed could induce lower concentrations of vitamin E in the liver of turkeys and can predispose the turkeys to knockdown syndrome.

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Antiprotozoal Agents; Diet; Dietary Supplements; Drug Interactions; Liver; Monensin; Muscle, Skeletal; Muscular Diseases; Poultry Diseases; Turkeys; Vitamin E; Vitamins

A real-time quantitative PCR assay targeting a 16S-23S intergenic spacer region sequence was devised to measure the sizes of populations of Lactobacillus salivarius present in ileal digesta collected from broiler chickens. This species has been associated with deconjugation of bile salts in the small bowel and reduced broiler productivity. The assay was tested as a means of monitoring the sizes of L. salivarius populations from broilers fed diets with different compositions, maintained at different stocking densities, or given the antimicrobial drugs bacitracin and monensin in the feed. Stocking densities did not influence the numbers of L. salivarius cells in the ileum. A diet containing meat and bone meal reduced the size of the L. salivarius population relative to that of chickens given the control diet, as did administration of bacitracin and monensin in the feed. These changes in the target bacterial population were associated with improved broiler weight gain.

Topics: Animals; Anti-Bacterial Agents; Bacitracin; Chickens; DNA, Bacterial; Ileum; Lactobacillus; Monensin; Polymerase Chain Reaction; Poultry Diseases

Two resistant lines of Eimeria tenella (H) to monensin were developed after 35 passages in chickens medicated with 100-125 ppm or 125-200 ppm monensin in the diet. Drug sensitivity of the induced lines to different level drugs were estimated with mean lesion scores (LS), mean oocyst productions (OP), percentage optimum anticoccidial activity (POAA), reduction of lesion scores (RLS), relative oocyst production (ROP), anticoccidial index (ACI) and global index (GI), respectively. Membrane fluidity of sporozoites of the sensitive line (i.e. the parent line, coded as MON-S((S))) and two resistant lines (coded as MON-R((S))-1 and MON-R((S))-2) with and without in vitro exposure to monensin were determined. Membrane fluidity of MON-R((S))-1 and MON-R((S))-2 were significantly lower than that of MON-S((S)). In vitro exposure to monensin significantly increased membrane fluidity of MON-S((S)), but had a much less effect on those of MON-R((S))-1 and MON-R((S))-2. Sporozoits of the MON-S((S))and MON-R((S))-2 with or without in vitro exposure to monensin were examined by SEM, and the sensitive sporozoites (MON-S((S))) appeared swollen and bulgy after treatment with monensin, while there was no obvious morphological deformation in the resistant sporozoites (MON-R((S))-2). The results suggest that the altered membrane fluidity in the membranes of E. tenella may be related to the decreased sensitivity to monensin.

Topics: Animals; Cecum; Chickens; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria tenella; Fluorescence Polarization; Membrane Fluidity; Microscopy, Electron, Scanning; Monensin; Parasitic Sensitivity Tests; Poultry Diseases; Sporozoites

Coccidiosis, caused by Eimeria species, is a serious economic disease of chickens (Gallus gallus) and the search for vaccines to control the disease is intensifying especially with the increasing threat of drug resistance. A live attenuated multi-valent ionophore-tolerant Eimeria vaccine has been developed that contains three ionophore-resistant Eimeria species, E. tenella, E. maxima and E. acervulina. The attenuated lines were derived from virulent field strains resistant to monensin ionophore by selection for early development in chicks. The vaccine was administered by gavage and through drinking water to broiler chickens, Chinese Yellow strain, reared in wire cages. Vaccinated medicated birds performed better than vaccinated unmedicated and medicated unvaccinated groups. The final mean weights of vaccinated medicated birds were significantly higher (P<0.05), and a better vaccine protection index, using both vaccinating methods, was achieved. Results indicated that concomitant use of ionophores and vaccines could be a useful adjunct to planned immunization in the control of coccidiosis.

Topics: Administration, Oral; Animals; Body Weight; Chickens; Coccidiosis; Eimeria; Feces; Female; Ionophores; Male; Monensin; Parasite Egg Count; Poultry Diseases; Protozoan Vaccines; Vaccination; Vaccines, Attenuated

The effect of sodium ions (Na+) on calcium (Ca2+)-mediated muscle damage in broiler chickens was investigated using an in vitro muscle preparation. Muscle Ca2+ accumulation was determined by 45Ca2+ uptake. Muscle damage was assessed by measurement of the efflux of the intracellular enzyme creatine kinase (CK) into the incubation medium. Loading muscle cells with Na+ by means of the sodium ionophore monensin led to concentration-dependent (25 to 200 microM) increases in 45Ca2+ uptakes and corresponding and proportional CK losses. The greatest responses occurred at 100 microM ionophore or greater, reflected in a 49% increase (P < 0.05) in 45Ca2+ uptake and an associated 140%-fold increase (P < 0.001) in CK efflux. Inhibition of muscle Na+/K+-ATPase activity with ouabain (2 mM) induced a 56% increase in 45Ca2+ uptake and a 60%-fold increase (P < 0.001) in total CK loss. The combined use of ionophore and ouabain resulted in 90 and 130%-fold elevations in 45Ca2+ uptake and CK loss, respectively. In monensin-treated muscles, inhibition of external Ca2+ influx from the incubation medium by chelation with 1,2 bis(2-aminophenoxy)ethane-N,N,N',N' tetracetic acid (5 mM) markedly reduced 45Ca2+ uptake (38%: P < 0.05) but increased CK release by 85% (P < 0.001). The results demonstrate that initial elevations in muscle Na+ can facilitate increases in muscle Ca2+ and lead to alterations in muscle cell membrane integrity and CK loss. The Na+-induced increases in myocellular Ca2+ may be mediated via direct extracellular Ca2+ entry or redistribution from internal Ca2+ stores. It is proposed that in order to reduce or prevent myopathies in poultry, exposure to conditions that may lead to elevations in muscle Na+ (e.g., increased muscle activity and stress or accidental ionophore toxicosis) should be avoided. The findings of this study have implications for management strategies of bird welfare, muscle pathology, and product quality.

Topics: Animals; Biological Availability; Calcium; Calcium Radioisotopes; Chickens; Female; Monensin; Muscle, Skeletal; Muscular Diseases; Ouabain; Poultry Diseases; Sodium; Sodium-Potassium-Exchanging ATPase

Eimeria parasites were isolated from Nanhai Guangdong province (southern China) and studied in chickens in wire cages to evaluate their drug resistance against commonly used ionophores: monensin (100 mg/kg of feed), lasolacid (90 mg/kg), salinomycin (60 mg/kg), maduramicin (5 mg/kg) and semduramicin (25 mg/kg). Chinese Yellow Broiler Chickens were infected with 40,000 crude sporulated Eimeria oocysts at 15 days of age and prophylactic medication commenced a day prior to infection. Drug resistance was assessed for each ionophore drug by calculating the anticoccidial index (ACI) and percentage optimum anticoccidial activity (POAA) based on relative weight gain, rate of oocyst production and lesion values. Results revealed that Nanhai Eimeria oocysts comprising of E. tenella, E. maxima and E. acervulina, were resistant to monensin, sensitive to both salinomycin and lasolacid and partially sensitive to maduramicin and semduramicin. By selection for early development of oocysts during passage through chickens, the prepatent time of E. tenella, E. maxima and E. acervulina were reduced by 49, 36 and 22 h, respectively. The precocious lines are less pathogenic than the parent strains from which they were selected and conferred a satisfactory protection for chickens against coccidiosis. These ionophore-tolerant precocious lines could have wider applications in the development of anticoccidial vaccines for sustainable control of coccidiosis.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria; Eimeria tenella; Ionophores; Lactones; Lasalocid; Monensin; Nigericin; Oocysts; Parasitic Sensitivity Tests; Poultry Diseases; Pyrans; Random Allocation; Treatment Outcome

The effects of diclazuril and monensin, when included in the feed of turkeys from 0 to 10 wk, upon performance and development of immunity to Eimeria species was investigated. Birds were initially inoculated with a low dose of oocysts of three species of Eimeria at 3, 5, 7, and 9 days of age in order to simulate a natural infection. Weight gain and feed intake from 0 to 6 wk of age was significantly greater in medicated birds compared with those that received no anticoccidial medication. Weight gain and feed intake from 6 to 10 wk was greater in birds that received diclazuril than in unmedicated birds. No differences in performance were evident after drug withdrawal from 10 to 16 wk. Immunity to Eimeria species developed by 10 wk in birds that received no anticoccidial medication but did not develop in those given diclazuril or monensin.

Topics: Animal Feed; Animals; Body Weight; Coccidiosis; Coccidiostats; Eating; Eimeria; Immunity, Innate; Monensin; Nitriles; Poultry Diseases; Triazines; Turkeys

A live attenuated anticoccidial vaccine (Paracox) was compared with a nicarbazin-monensin anticoccidial drug shuttle programme in three crops of Italian broilers, comprising a total of 290,405 chickens. All birds received the antibiotic growth promoter avilamycin. No coccidiosis was evident during the trials, but the occurrence of oocysts in the litter demonstrated that a natural challenge was present. Vaccinated birds consistently performed at least as well as those treated with the anticoccidial drug shuttle. The final mean weights of vaccinated birds were significantly greater (P < 0.001) than those of birds treated with anticoccidial drugs, both for females at 36/37 days and males at 56 days. Feed conversion ratios, total mortality including culls, the proportion of rejects at the processing plant, and the moisture content of the litter were not significantly different between the two control methods. Growth curves showed that there was no post-vaccinal growth check in the vaccinated birds and no intolerance of the anticoccidial drug treatment. There was no overall seasonal effect, regardless of treatment, on the performance of the three crops reared from November 1997 to July 1998. These findings suggest that the use of this vaccine is likely to enable the replacement of anticoccidial drug shuttle programmes in broilers reared under conditions similar to those used in these Italian flocks.

Topics: Animal Feed; Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Female; Italy; Male; Monensin; Nicarbazin; Oligosaccharides; Oocysts; Poultry Diseases; Protozoan Vaccines; Vaccination; Vaccines, Attenuated; Weight Gain

The efficacy of different concentrations of monensin in turkeys exposed to field isolates of Eimeria and the effect of the withdrawal of monensin from their diet were investigated. Results of a battery study indicated that 66 ppm monensin was effective against three species of Eimeria in the turkey. In floor pens in which poults were exposed to infection, use of 59.5, 79.4, and 99.2 ppm monensin resulted in reduced mortality and improved feed conversion at 3 wk of age compared with birds that had received no medication. Poults given 59.5 ppm monensin weighed more and had a better feed conversion at 3 wk than poults given 79.4 or 99.2 ppm monensin, but at 10 wk no differences in the body weight or feed conversion of poults given different concentrations of drug were apparent. At 14 wk (and from 10 to 14 wk), poults that had been given 99.2 ppm monensin had a lower feed intake and weighed less than birds that had been given 59.5 ppm of the drug but there were no significant differences in feed conversion. There was no significant difference in the weight gain or feed conversion of poults from 10 to 14 wk of age whether monensin was present in the feed or had been withdrawn. No evidence of compensatory growth was found in the present study.

Topics: Animals; Coccidiosis; Coccidiostats; Eimeria; Feces; Monensin; Parasite Egg Count; Poultry Diseases; Turkeys

Topics: Animals; Calcium; Chickens; Creatine Kinase; Monensin; Muscle, Skeletal; Muscular Diseases; Poultry Diseases; Species Specificity

Seven anticoccidial drugs commonly used in poultry (diclazuri), monensin, salinomycin, halofuginone, nicarbazin, robenidine, amprolium, and lasalocid) were tested for residual activity after withdrawal. In each test, the products were given at the recommended level to cages of 10 broiler chickens. Oral inoculation with coccidia was given after withdrawal of medication. Birds pretreated with 1 ppm of diclazuril and inoculated with Eimeria tenella after drug withdrawal had normal weight gain and very low lesion scores. Residual activity depleted gradually over several days, as shown by higher lesion scores when medication was withdrawn for up to 3 days before inoculation. Similar results were observed when young birds were inoculated with a mixture of E. tenella, E. maxima and E. acervulina, and also when birds were given diclazuril to market weight (6 weeks of age) and inoculated with a mixture of six species of Eiméria (The above species plus E. brunetti, E. mitis, and E. necatrix) after withdrawal of medication for 2 days. In contrast, there was no evidence of residual anticoccidial activity with nicarbazin, halofuginone, lasalocid, amprolium, salinomycin or monensin. Overall, the residual activity was unique to diclazuril.

Topics: Amprolium; Animal Feed; Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria tenella; Feces; Female; Lasalocid; Male; Monensin; Nicarbazin; Nitriles; Piperidines; Poultry Diseases; Pyrans; Quinazolines; Quinazolinones; Random Allocation; Triazines

Coccidia were isolated from a commercial broiler farm with a history of suspected drug resistance. The sensitivity profiles of the Eimeria spp. isolates against the anticoccidial drugs nicarbazin (NIC), narasin (NAR), halofuginone (HAL), salinomycin (SAL), meticlorpindol plus methylbenzoquate (MET), and monensin (MON) at the recommended dose levels were followed in three battery trials (B1, B2, B3) corresponding to a field study over three periods of commercial broiler keeping (F1, F2, F3). Shuttle programs were performed in F1 (NIC/MON) and in F2 (MET/MON) while only SAL was used in F3. Eimeria acervulina and E. tenella were isolated from indicator birds in F1 while only E. acervulina could be found during F2 and F3. In trial B1 the isolate from F1 was identified as resistant against HAL and partly resistant against NIC and MON, the two drugs that were used in F1. Following the replacement of NIC in the starter feed by MET the respective isolate from F2 showed no resistance against ionophores (trial B2) while partial resistance against HAL was still present. Since SAL was the most efficient drug in B1 and B2 only this drug was applied in F3. Apart from a resistance against HAL no resistance against any of the other tested anticoccidials was found in the isolate from F3. SAL controlled coccidiosis efficiently in the field and best productivity was recorded in F3. This study shows that battery trials have a good predictive value in respect to the efficacy of anticoccidials under the conditions of commercial broiler production.

Topics: Animal Husbandry; Animals; Chickens; Clopidol; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria; Feces; Food Industry; Ionophores; Monensin; Nicarbazin; Piperidines; Poultry Diseases; Predictive Value of Tests; Pyrans; Quinazolines; Quinazolinones; Quinolones

The effects of the growth promoters avoparcin and avilamycin and the ionophore anticoccidials maduramicin, narasin and monensin on the growth of Clostridium perfringens (Cp) in the caeca and on performance of broiler chickens were tested in 2 experiments. The supplements were fed as single feed additives or in some combinations. No clinical signs or lesions caused by coccidia were observed in any of the studies. All supplements had an antibacterial effect on Cp and improved growth rate significantly. Carcass yield of birds fed growth promoters avilamycin or avoparcin was significantly higher compared with birds fed anticoccidials. These data indicate that, what concerns bird performance, during good hygienic conditions supplementation with antibiotic growth promoters may not be necessary when the diet is supplemented with an anticoccidial with antibacterial effects.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Cecum; Chickens; Clostridium Infections; Clostridium perfringens; Coccidiostats; Glycopeptides; Growth Substances; Ionophores; Lactones; Monensin; Oligosaccharides; Poultry Diseases; Pyrans; Random Allocation

Ten Eimeria field isolates from North Germany were studied in battery tests for sensitivity to selected anticoccidials. A high percentage of the Eimeria field isolates (9 out of 10) showed resistance to anticoccidials, mostly multiple resistance. Partial or complete resistance to maduramicin was found in 7 field isolates, to monensin in 6, to salinomycin in 5, to nicarbazin in 8, to halofuginone in 7, to robenidine and toltrazuril in 1, and to diclazuril in 2 field isolates. Multiple resistance had developed in 7 of the 10 isolates. Cross-resistance between maduramicin, monensin, and salinomycin occurred in 5 Eimeria isolates. One isolate showed cross-resistance between diclazuril and toltrazuril. From the resistant isolates 15 pure E. acerculina and 5 pure E. brunetti strains were obtained by single oocyst infections. Seven of the E. acerculina and 4 of the E. brunetti strains showed resistance or partial resistance that was also present in the original isolate. Ten of 11 resistant strains were multiply resistant.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Drug Resistance; Drug Resistance, Multiple; Eimeria; Germany; Lactones; Male; Monensin; Nicarbazin; Nitriles; Piperidines; Poultry Diseases; Pyrans; Quinazolines; Quinazolinones; Robenidine; Triazines

Three experiments (Exp.) were conducted to evaluate the interactive effects of dietary betaine (BET) and monensin (MON) in uninfected or Eimeria acervulina-infected chicks. The treatments were replicated with six (Exp. 1) or five (Exp. 2 and 3) pens of five chicks each. The experimental periods lasted 9 (Exp. 1 and 2) or 10 (Exp. 3) d each and the coccidiosis infections were established on Day 2 (Exp. 1 and 2) or Day 3 (Exp. 3) of the experiment. Average initial weight of the chicks was 101, 73, and 68 g in Exp. 1 to 3, respectively, and the initial age of the chicks was 5 (Exp. 1) or 4 (Exp. 2 and 3) d. A corn-soybean meal basal diet was used in each experiment. In Exp. 1, the effect of dietary BET (0, 0.1, or 0.5%) in uninfected or coccidiosis-infected (COC; 5 x 10(5) sporulated E. acervulina oocysts) chicks was investigated. In Exp. 2, the interactive effects of BET (0 or 0.1%) and MON (0 or 55 ppm) in uninfected or COC chicks were investigated in a 2 x 2 x 2 factorial arrangement of treatments. Experiment 3 was identical to Exp. 2, except the level of MON was 110 rather than 55 ppm. In Exp. 1, 2, and 3, COC reduced (P < 0.01) gain, feed intake (FI), feed efficiency (GF), and plasma carotenoid concentration (CAR) and increased (P < 0.01) lesion score (LS). In Exp. 1, gain and FI were decreased in uninfected chicks fed 0.1% BET but gain and FI were increased in COC chicks fed 0.1% BET (COC x BET quadratic, P < 0.01). Dietary BET linearly increased (P < 0.05) GF. In Exp. 2 and 3, MON increased (P < 0.01) gain, FI, GF, and CAR and decreased (P < 0.01) LS of COC chicks, but MON had no effect in uninfected chicks (COC x MON, P < 0.01). In Exp. 2, GF was increased more in chicks fed both MON and BET than in chicks fed MON (BET x MON, P < 0.06). In Exp. 3, BET increased GF of uninfected chicks fed MON and of COC chicks not fed MON (COC x BET x MON, P < 0.02). Betaine may have an effect on E. acervulina-infected chicks, but there is no conclusive evidence to indicate that the efficacy of MON is improved when fed in combination with BET.

Topics: Animal Feed; Animals; Betaine; Carotenoids; Chickens; Coccidiosis; Coccidiostats; Diet; Drug Interactions; Drug Therapy, Combination; Eating; Eimeria; Lipotropic Agents; Male; Monensin; Poultry Diseases; Random Allocation; Weight Gain

L6 myoblasts were used as an in vitro model to investigate the role of moniliformin and its interaction with monensin in turkey knockdown syndrome and sudden death syndromes in poultry. Cell viability and microscopic and ultrastructural alterations noted in L6 myoblasts cultured in the presence of moniliformin (0.0-0.3 microgram/microliter) were compared to those observed in parallel cultures also containing one of the following compounds: selenium (0-0.004 ng/microliter), thiamine (0-0.3 microgram/microliter), or pyruvate (0-0.46 microgram/microliter). Marked dilation of the RER, membranous whorls, glycogen deposition, membrane-bound cytoplasmic inclusions and necrosis were observed in myoblasts exposed to 0.03-0.30 microgram moniliformin/microliter medium. Supplementation of medium with thiamine and pyruvate, or selenium, provided significant protection to cells exposed to 0.0-0.3 microgram/microliter or 0.0-0.15 microgram moniliformin/microliter, respectively. Dose-dependent differences in protein and ATP production were not detected. Myoblasts grown in medium containing 0-0.15 microgram moniliformin/microliter and 7.5-50.0 microM A23187, beauvericin or monensin had degrees of cytotoxicity similar to parallel cultures receiving only an ionophore. L6 myoblasts were a useful model of moniliformin toxicosis. The findings of this study suggest cytotoxicity due to moniliformin in L6 myoblasts may be due in part to oxidative damage and altered pyruvate metabolism, and that moniliformin does not predispose myoblasts to ionophore toxicosis. This study supports the results of in vivo investigations in poultry that moniliformin and monensin do not act synergistically to induce knockdown or monensin toxicosis.

Topics: Adenosine Triphosphate; Animals; Cell Line; Cyclobutanes; Ionophores; Models, Biological; Monensin; Mycotoxins; Poultry Diseases; Protein Biosynthesis; Rats; Turkeys

The performance of broilers reared in floor pens and given monensin in the feed at 121 ppm was compared with that of birds given no drug. Feed intake and BW gain of medicated birds was significantly lower than that of unmedicated birds from 0 to 22 d of age. Feed intake and feed conversion of medicated birds was significantly reduced, compared with unmedicated birds, from 22 to 53 and 0 to 60 d of age. Total mortality, and mortality due to leg abnormalities from 22 to 53 and 0 to 60 d, was significantly lower in birds given monensin. There was no difference in the incidence of tibial dyschondroplasia (TD) by 60 d. No differences in mortality due to pulmonary hypertension syndrome (PHS) were observed for any age period. Birds removed from pens at 28 d that had received monensin had lower hematocrit and percentage saturation of hemoglobin with oxygen in the blood than unmedicated birds. No differences in these variables were found at 54 d. There were no differences in the right ventricle weight: total ventricular weight ratios or electrocardiogram lead II values at 28 or 54 d. The results indicate that PHS does not occur more frequently in broilers medicated with monensin.

Topics: Animals; Ascites; Chickens; Eating; Food, Fortified; Incidence; Male; Monensin; Poultry Diseases; Weight Gain

Liver-porphyrin levels were found to have increased during sub-acute lead toxicosis. The presence of selenium or monensin in the diet of lead-intoxicated birds resulted in a further increase of liver-porphyrin levels. The results of this study indicate the presence of an interaction between lead and selenium or monensin in producing an increase in porphyrins in the liver tissue of broiler chickens.

Topics: Animals; Chickens; Lead; Lead Poisoning; Liver; Monensin; Porphyrins; Poultry Diseases; Selenium

The sensitivity of field isolates of Eimeria to monensin was investigated following the use of a commercial coccidiosis vaccine. Monensin was not effective against isolates from five commercial farms where ionophores had been used for many flocks. Monensin was more effective, however, against isolates obtained from the same farms following the use of a coccidiosis vaccine. No further improvement in drug efficacy was noted after five successive flocks in which the vaccine was used.

Topics: Animals; Chickens; Coccidiosis; Eimeria; Male; Monensin; Poultry Diseases; Protozoan Vaccines; Treatment Outcome; Weight Gain

The efficacy of semduramicin (AVIAX), a novel polyether ionophore, was profiled in a series of 57 battery tests conducted in the United States and the United Kingdom. The studies employed mixed and monospecific infections of Eimeria acervulina, Eimeria mivati/Eimeria mitis, Eimeria brunetti, Eimeria maxima, Eimeria necatrix, and Eimeria tenella derived from North American and European field isolates. Ten-day-old broiler cockerels in pens of 8 to 10 birds were continuously medicated in feed beginning 24 h before challenge in tests of 6 to 8 days' duration. At the use level of 25 ppm, semduramicin effectively controlled mortality, lesions, and weight gain depression that occurred in unmedicated, infected controls for all species. In comparison with 60 ppm salinomycin, semduramicin significantly (P < .05) improved weight gain against E. brunetti and E. tenella, lesion control against E. brunetti and E. maxima, and the control of coccidiosis mortality against E. tenella. Salinomycin was superior (P < .05) to all treatments in maintenance of weight gain and control of lesions for E. acervulina. Maduramicin at 5 ppm was inferior (P < .05) to semduramicin in control of E. acervulina and E. maxima lesions, but was superior (P < .05) to all treatments in maintenance of weight gain and control of lesions in E. tenella infections. The data indicate that semduramicin at 25 ppm is well tolerated in broilers and possesses broad spectrum anticoccidial activity.

Topics: Animals; Anti-Bacterial Agents; Chickens; Coccidiosis; Eimeria; Lactones; Male; Monensin; Nigericin; Poultry Diseases; Pyrans; Species Specificity; Treatment Outcome; Weight Gain

Experiments were carried out to investigate why the anticoccidial ionophore monensin is more potent against the coccidium Eimeria tenella in chickens fed on a maize-based diet (as in the USA) than in chickens fed on a wheat-based diet (as in the UK). The explanation seems to be that the pathogenicity of E. tenella is lower in maize-fed chickens than in wheat-fed chickens, whether monensin is present in the diet or not. Possible reasons for this are suggested. The better survival of maize-fed birds may be partly due to protective effects of the higher concentrations of vitamins A and E derived from their diet. Furthermore, the higher concentrations of niacin and riboflavin in wheat than in maize may enhance coccidial pathogenicity. These opposing factors might combine to cause equivalent infection levels to produce more severe coccidiosis in chickens fed on a wheat-based diet than on a maize-based diet.

Topics: Animal Feed; Animals; Coccidiosis; Eimeria tenella; Male; Monensin; Poultry Diseases; Specific Pathogen-Free Organisms; Triticum; Zea mays

Topics: Animal Feed; Animals; Female; Monensin; Muscular Diseases; Poultry Diseases; Turkeys

Two trials were conducted to compare the efficacy of currently approved anticoccidials for turkeys against challenge using a field isolate of mixed Eimeria species; E. adenoides, E. gallopavonis, and E. meleagrimitis. Poults in wire-floored cages were fed unmedicated diets from day-old to 3 wk of age. Diets were supplemented with either amprolium (AMP, 125 mg/kg), butynorate (BUT, 375 mg/kg), monensin (MON-60, 60 mg/kg; MON-100, 100 mg/kg), halofuginone (HAL; 3 mg/kg), zoalene (ZOA; 125 mg/kg), or sulfadimethoxine plus ormetoprim (SUL + ORM, 62.5 mg/kg and 37.5 mg/kg, respectively). After 2 days on the test diets, poults were individually weighed and inoculated with sporulated coccidial oocysts from the field isolate. Total fecal collections were obtained for Days 0 to 5 and 6 to 10 to estimate oocyst output. At 10 days postinoculation, the birds were individually weighed and killed to determine severity of intestinal lesions. The HAL and MON were most effective and AMP, ZOA, and SUL + ORM were least effective in maintaining weight and in reducing the severity of intestinal lesions. All the coccidiostats tested reduced oocyst passage, but poults fed HAL produced fewer oocysts. The results demonstrated differences in efficacy among anticoccidials with the more recently approved drugs providing the best protection against coccidiosis.

Topics: Amprolium; Animals; Coccidiosis; Coccidiostats; Dinitolmide; Feces; Intestines; Male; Monensin; Organotin Compounds; Piperidines; Poultry Diseases; Pyrimidines; Quinazolines; Quinazolinones; Sulfadimethoxine; Turkeys; Weight Gain

A new polyether antibiotic CP-82,996 (C50H86O16) was isolated by solvent extraction from the fermentation broth of Actinomadura sp. (ATCC 53764). Following purification by silica gel column chromatography and crystallization, the structure of CP-82,996 was determined by a single crystal X-ray analysis. The structure is closely related to monensin, but is unique in that it contains two sugar groups, whereas monensin has none. The 1H and 13C NMR chemical shifts and assignments for CP-82,996 were elucidated, and they were compared with those determined previously for monensin. CP-82,996 is active against certain Gram-positive bacteria, and is a very potent anticoccidial agent. It effectively controlled chicken coccidiosis caused by several Eimeria species at 5-10 ppm in feed, and is 10-20 times more potent than monensin.

Topics: Animals; Anti-Bacterial Agents; Bacteria; Chickens; Coccidiosis; Fermentation; Magnetic Resonance Spectroscopy; Mass Spectrometry; Microscopy, Electron, Scanning; Molecular Structure; Monensin; Nocardiaceae; Poultry Diseases; X-Ray Diffraction

The effect exerted by overdosage of monensin, an ionophore antibiotic, on the lipid peroxide status of broiler chickens was studied. Three-week-old broiler cockerels were given 150 mg monensin/kg body mass through a tube, and the malondialdehyde (MDA) concentration, glutathione peroxidase (GSH-Px) and catalase activity of the liver and breast muscle, and MDA concentration and GSH-Px activity of the blood plasma were determined. Liver MDA and catalase values rose rapidly and significantly during the experimental period. GSH-Px activity initially decreased, then tended to rise. Blood plasma and breast muscle variables did not change during the experiment. Acute monensin poisoning induced substantial enhancement of lipid peroxidation processes in the liver, while it did not appreciably affect the lipid peroxide status of the blood plasma and breast muscle. The role of the observed phenomenon in the rather complex pathogenesis of monensin poisoning is not known sufficiently. Further studies are needed to elucidate the problem.

Topics: Animals; Catalase; Chickens; Drug Overdose; Lipid Peroxidation; Male; Malondialdehyde; Monensin; Poultry Diseases

An experiment was conducted with 5- to 18-day-old Arbor Acres broiler chicks to evaluate the interaction of sodium zeolite A (NZA) and monensin in uninfected and in coccidiosis-infected chicks. Sodium zeolite A (0 and .75%) or monensin (0 and 121 ppm), or both, were fed to uninfected chicks or to chicks infected with 4 x 10(5) sporulated, Eimeria acervulina oocysts, resulting in a 2-by-2-by-2 factorial arrangement of treatments. Coccidial infection reduced (P less than .01) weight gain, feed intake, feed efficiency, percentage of bone ash and of bone calcium; but the infection increased (P less than .05) bone Zn percentage. Monensin alleviated (or at least partially so) the adverse effects of the coccidial infection on weight gain, feed intake, feed efficiency and percentage of bone ash (coccidiosis by monensin, P less than .01). In addition, monensin increased the bone-calcium (P less than .06) and zinc content (P less than .02) in uninfected chicks and in those infected with coccidiosis. Sodium zeolite A tended to reduce feed intake by coccidiosis-infected chicks (coccidiosis by NZA, P less than .07), but increased (P less than .01) the bone zinc and decreased (P less than .01) serum inorganic phosphorus in uninfected chicks and in those infected with coccidiosis.

Topics: Aluminum Silicates; Animals; Chickens; Coccidiosis; Eating; Ionophores; Monensin; Poultry Diseases; Weight Gain; Zeolites

Two series of experiments were conducted to assess the relative ability of strains of Eimeria acervulina and Eimeria tenella to develop resistance to monensin (MON), nicarbazin (NIC), and the monensin plus nicarbazin combination (MON plus NIC). The studies were designed so that drug concentrations in the selection experiments were increased whenever possible. During selection, E. acervulina increased its reproductive index in the presence of NIC or MON plus NIC, equivalent selection in the presence of MON resulted in only a slight increase in reproductive ability. Eimeria tenella, however, was unable to increase its reproductive capacity to the respective drugs. Sensitivity tests after 60 generations of selection revealed that patterns of resistance development for E. acervulina and E. tenella corresponded with the changes in reproductive indices established in the selection experiments. Thus, results of these tests indicate that E. acervulina possesses the ability to develop resistance to NIC and MON plus NIC. Under essentially the same conditions of selection, E. tenella developed only partial resistance to the respective drugs.

Topics: Animals; Chickens; Coccidiosis; Drug Combinations; Drug Resistance; Eimeria; Male; Monensin; Nicarbazin; Poultry Diseases

Lasalocid and monensin are widely used to control coccidiosis in broilers, but not in turkey poults. Four feeding trials were conducted to determine the performance of turkey poults when these compounds were used singly or in combination with 100 ppm of furazolidone. Bodyweights and feed consumption were significantly depressed for five weeks after hatching by 150 ppm of lasalocid. Combining furazolidone with lasalocid ameliorated the toxic effect of lasalocid. Bodyweights were significantly depressed by 150 ppm of monensin in the fifth week after hatching, but there was no significant depression in feed consumption. Furazolidone exacerbated any toxic effects of monensin. Data indicate that monensin may be used safely at dosages greater than the recommended level of 60 to 99 ppm, but should not be used in combination with furazolidone.

Topics: Animal Feed; Animals; Bacterial Infections; Body Weight; Coccidiosis; Drinking; Drug Interactions; Eating; Furazolidone; Lasalocid; Male; Monensin; Poultry Diseases; Random Allocation; Turkeys

Four chick and five poult trials were conducted in order to investigate the anticoccidial efficacy of monensin against Eimeria mitis in chickens and Eimeria dispersa in turkeys. The chicks were fed a basal diet with either 0 or 100 ppm of monensin. The poults were fed a basal diet with either 0 or 60 ppm of monensin. Two days after the initiation of each experiment, the chicks and poults were crop-intubated with oocysts of E. mitis and E. dispersa, respectively. A group was also included that was not infected and not medicated. Growth and feed intake were recorded. At 6 or 7 days postinoculation, the birds were killed by cervical dislocation and were scored for the incidence and severity of intestinal abnormalities. The Eimeria mitis infection reduced (P less than .01) gain and the feed:gain ratio, compared with uninfected birds; the E. dispersa infection only reduced (P less than .05) gain. Although well-defined, discrete lesions were not observed, marked intestinal abnormalities were noted in birds infected with either E. mitis or E. dispersa. Also, the infected, unmedicated birds had increased (P less than .01) intestinal scores compared with uninfected birds or those with infection but treated with monensin. Monensin eliminated the reduction in gain and feed efficiency seen in the infected birds. The infected birds fed monensin had intestinal scores, gain, and feed:gain ratios similar (P greater than .10) to those for the birds that were not infected and that did not receive medication.

Topics: Animals; Chickens; Coccidiosis; Eating; Intestines; Male; Monensin; Poultry Diseases; Turkeys; Weight Gain

Field observations suggest that coccidiosis is a common cause of death in broiler chicken flocks fed diets containing sufficient amounts of ionophore antibiotics (monensin, narasin, etc.) and contaminated with mycotoxins, particularly with T-2 fusariotoxin. To study this phenomenon, broiler chickens fed diets containing different amounts of T-2 toxin and free from monensin, or containing a preventive dose (100 mg/kg of feed) of monensin, were infected experimentally with coccidian oocysts. In all groups fed a diet containing monensin plus T-2 toxin severe clinical symptoms of coccidiosis (blood-stained faeces etc). occurred. Deaths and retarded growth depended on the toxin dose and were considerable. The body mass gain of chicks fed a diet containing monensin and T-2 toxin but not infected with coccidia was inferior to that of groups fed diets which contained either monensin or T-2 toxin (experiment 2). On the basis of these findings a negative interaction of the two compounds is assumed. This seems to be supported by the results of experiment 3, i. e. the finding that the lethal dose of narasin, a compound closely related to monensin both in chemical structure and mechanism of action, proved to be much lower (LD50 = 102 mg/kg body mass) for chickens fed a diet supplemented with T-2 toxin than for the control chickens (LD50 = 176 mg/kg body mass). The present results suggest that the feeding of diets severely contaminated with T-2 toxin may alter the anticoccidial efficacy of monensin.

Topics: Animals; Chickens; Coccidiosis; Drug Interactions; Female; Male; Monensin; Poultry Diseases; Sesquiterpenes; T-2 Toxin

Isolates of Eimeria species obtained from broiler or from breeder farms were compared for their sensitivity to two ionophorous anticoccidial drugs, monensin and lasalocid. All of 25 isolates from broiler farms were resistant to 100 ppm monensin or 90 ppm lasalocid, while 14 of 16 isolates were resistant to monensin and seven of 16 to lasalocid from breeder farms (replacement layer and broiler breeder).

Topics: Animals; Cecum; Chickens; Coccidiosis; Eimeria; Feces; Lasalocid; Monensin; Poultry Diseases

Narasin is effective against all species of chicken coccidia when tested in battery cage and floor pen studies. To confirm the efficacy of narasin under practical broiler production conditions, the drug was fed at concentrations of 60 ppm or 80 ppm to broiler chickens being raised by six different commercial broiler producers in five different geographic areas. Monensin was fed in each trial at a concentration of 100 ppm or 121 ppm as a reference control. The usual management practices of each of the integrated broiler companies were followed throughout the respective trials. Nine trials were conducted and approximately 100,000 broilers were tested for each treatment. No adverse reactions attributable to treatments were observed in any of the trials, and performance results obtained with narasin-medicated birds were generally comparable with those obtained with monensin-medicated birds in the same trial. These findings support the conclusion that narasin at final feed concentrations in the range of 60 to 80 ppm can be safely and effectively used as an anticoccidial agent in commercial broiler production facilities.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Monensin; Poultry Diseases; Pyrans

The activities of five anticoccidials were compared against Eimeria species in/of chickens, in controlled in vivo and in vitro laboratory studies. Two more recent and potent market entries (maduramicin and halofuginone) were compared with three older polyether antibiotic anticoccidials (monensin, lasalocid and salinomycin). Halofuginone, lasalocid, maduramicin, monensin and salinomycin were evaluated at 3, 125, 5, 120 and 66 ppm, respectively, of active drug in the diets. At these levels, all five drugs demonstrated significant activity against Eimeria tenella, E. maxima, E. necatrix, E. brunetti and E. acervulina (in vivo). Monensin was least effective against E. tenella, and one of the lesser efficacious drugs against E. necatrix, maduramicin, was least effective against E. maxima. In studies of single Eimeria species infections, comparable weight gains were noted for the drugs. In the mixed Eimeria species infections, however, birds treated with maduramicin had significantly higher weight gains than did birds medicated with monensin. Unlike in vivo potencies, titration in vitro indicated that monensin was most potent (active at 10(-6) mcg ml-1), and maduramicin and lasalocid least potent (inactive at less than or equal to 10(-3) mcg ml-1).

Topics: Animals; Anti-Bacterial Agents; Body Weight; Chickens; Coccidiosis; Coccidiostats; Eimeria; Female; Ionophores; Lactones; Lasalocid; Male; Monensin; Piperidines; Poultry Diseases; Pyrans; Quinazolines; Quinazolinones

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Ionophores; Lasalocid; Monensin; Poultry Diseases; Pyrans

Topics: Animal Feed; Animals; Chickens; Coccidiosis; Eimeria; Monensin; Poultry Diseases; Pyrans

Topics: Animals; Chickens; Coccidiosis; Dose-Response Relationship, Drug; Eimeria; Monensin; Poultry Diseases; Pyrans

Topics: Animal Feed; Animals; Chickens; Coccidiostats; Female; Growth Disorders; Male; Monensin; Poultry Diseases; Pyrans

Experiments were conducted with crossbred male chicks to evaluate the interactions among roxarsone (50 mg/kg), monensin (121 mg/kg), and copper sulfate (100 mg/kg) as treatments for experimental Eimeria tenella and E. acervulina infections. When diets containing monensin, roxarsone, or a combination of both were offered to chicks for 15 min or 1, 3, 5, or 8 days prior to E. tenella challenge (5 X 10(4) sporulated oocysts), monensin fed for 15 min or roxarsone fed for 1 day prior to challenge prevented morbidity. A mixed infection of E. tenella and E. acervulina (5 X 10(4) and 4 X 10(5) sporulated oocysts, respectively) reduced gain and gain:feed conversion ratios and caused severe duodenal and cecal lesions at Day 6 of the experiment. Infected chicks gained faster when diets were supplemented with either monensin or roxarsone, but monensin produced a larger response than roxarsone. The mixed infection decreased shank pigmentation, with amelioration activity evident from monensin but not from roxarsone. Lesion scores at Day 6 indicated markedly reduced lesions in the duodenum due to monensin but not due to roxarsone; likewise, reductions in cecal lesions occurred in birds fed roxarsone but less so in birds fed monensin. Lesion scores showed little evidence of additivity due to monensin and roxarsone. In general, copper sulfate exerted no independent or interactive effect on any of the parameters evaluated. In a subsequent experiment, the effect of feeding roxarsone in combination with the biological reducing agent, cysteine, was evaluated in E. tenella-infected chicks. Rate and efficiency of gain were improved and lesion scores were reduced by supplementary roxarsone.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Arsenicals; Chickens; Coccidiosis; Copper; Copper Sulfate; Drug Interactions; Drug Therapy, Combination; Male; Monensin; Poultry Diseases; Roxarsone

Discontinuous medication with toltrazuril, given in the drinking water at a concentration of 50 ppm, was effective in controlling infection resulting from repeated inoculation of oocysts of a line of E. tenella partly resistant to monensin. Treatment was very effective when the drug was given for periods of 3 days, on two or three occasions at weekly intervals. Monensin, at a concentration of 120 ppm, given continuously in the feed was only partially effective. Following treatment with toltrazuril, birds inoculated with high doses of oocysts were immune to subsequent challenge. It is suggested that discontinuous medication with toltrazuril in the drinking water might provide an alternative to the current practice of incorporating drugs continuously in the feed.

Topics: Administration, Oral; Animals; Chickens; Coccidiosis; Drug Resistance, Microbial; Erwinia; Monensin; Poultry Diseases; Triazines

Chemoprophylaxis of Cryptosporidium baileyi infections was attempted by feeding 4 groups of chicks diets containing 3 mg of halofuginone/kg of feed, 60 mg of salinomycin/kg, 75 mg of lasalocid/kg, or 110 mg of monensin/kg. Rations were fed 5 days before oral or intratracheal inoculation with oocysts and were continued for 20 days. None of the drugs prevented C baileyi infections. Clinical signs of respiratory tract disease and gross lesions of airsacculitis were observed in intratracheally inoculated birds in all treatment groups and nonmedicated controls. Orally inoculated birds did not develop clinical signs of infection. Pathogenic bacteria were not isolated from the respiratory tract systems of any chicks. Halofuginone delayed the establishment of infections of the bursa of Fabricius and cloaca, but not of the trachea.

Topics: Animals; Chickens; Coccidiostats; Cryptosporidiosis; Lasalocid; Monensin; Piperidines; Poultry Diseases; Pyrans; Quinazolines; Quinazolinones

Prophylactic levels of three ionophorous antibiotics, monensin, salinomycin, and lasalocid, were administered to groups of chickens and turkeys. All three ionophores markedly inhibited invasion of cecal tissues by sporozoites of ionophore-sensitive (IS) Eimeria tenella. Monensin and salinomycin also reduced invasion in turkeys by sporozoites of E. adenoeides, but lasalocid only minimally inhibited invasion. Invasion of ceca of monensin-medicated chickens was significantly greater by sporozoites of ionophore-resistant (IR) E. tenella than of the IS isolate. Concomitant experiments showed significant differences in [14C]monensin accumulation among IS and IR isolates of E. tenella. The decreased uptake of monensin by the IR isolates appeared to be accompanied by a decrease in responsiveness to the activity of monensin as well as to two other ionophores, salinomycin and narasin in cell culture. The amount of monensin, salinomycin or narasin required to inhibit development of E. tenella by 50% was 20 to 40 times higher for the IR isolates than for the IS ones. Collectively, the data suggest that differences in ionophore accumulation by IS and IR isolates of E. tenella might reflect differences in membrane chemistry and that these differences are responsible for the expressions of resistance that were observed in these studies. This expression of resistance appears to be common to all ionophores tested.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Drug Resistance; Ionophores; Lasalocid; Monensin; Poultry Diseases; Pyrans; Turkeys

Oocysts of fowl coccidia, suspended in a 12% aqueous solution of alginic acid, were dropped into 5% calcium chloride solution to form beads. Following ingestion by chicks, excystation of sporozoites was not affected. Oocyst viability was best when beads were air-dried to 33% of their original weight and stored in airtight containers at 4 degrees C. Infectivity was fully maintained for 8 weeks. Trickle infection, using beads administered orally to 2- or 3-week-old chickens, or mixed daily in food of chicks from 1-day-old, established a high level of immunity. This method of oocyst administration offers some practical advantages for the conduct of immunity and chemotherapy experiments.

Topics: Alginates; Animals; Capsules; Chickens; Coccidiosis; Eimeria; Male; Monensin; Poultry Diseases

Experiments were performed with growing chicks to assess the effects of rations deficient in energy and protein on feed intake, quantity of monensin ingested, and overall anticoccidial efficacy. Experiment 1 employed a 4 X 2 X 2 factorial design where four levels of monensin (0, 70, 90, and 110 ppm) were added to rations containing either 17 or 23.5% crude protein. In Experiment 2, identical levels of monensin were added to diets containing either 2600 or 3200 kcal metabolizable energy/kg. Both studies were conducted in the presence and the absence of infections produced by Eimeria acervulina, E. maxima, and E tenella. Chicks fed diets deficient in protein consumed significantly more feed and gained less weight than those fed rations adequate in protein. Likewise, protein-deficient chicks consumed more monensin per kilogram of body weight gain. In Experiment 2, weight gain and feed intake were greater in birds fed adequate energy, but the quantity of monensin consumed per kilogram of weight gain was greatest in energy-deficient chicks. In both experiments coccidial lesions and oocyst output were controlled more effectively as monensin dosage was increased. Neither protein nor energy interacted significantly with monensin when lesion scores and oocyst output were evaluated. Thus, these studies indicate that coccidiosis control offered by the monensin concentrations studies is independent of the protein or energy content of the ration.

Topics: Animal Feed; Animals; Chickens; Coccidiosis; Dietary Proteins; Eating; Energy Metabolism; Furans; Male; Monensin; Poultry Diseases

Symptoms of paralysis were observed in seven-week-old turkeys on a farm following administration of sulphachlorpyrazine for coccidiosis. Paralysis was particularly common in the females which were separated from the male birds. Of monensin 122 ppm were found to be present in the feed, whereas the amount stated on the label was 100 ppm. When a new batch was substituted for this feed, the symptoms abated. As the result of a possible interaction of monensin and sulphachlorpyrazine, mortality was 1.7 per cent in the male and 11.2 per cent in the female birds.

Topics: Animals; Coccidiostats; Female; Furans; Male; Monensin; Paralysis; Poultry; Poultry Diseases; Sulfanilamides; Turkeys

Four isolates of Eimeria tenella obtained from the field were partially resistant to monensin. This resistance was not lost after 10 passages in unmedicated chickens, indicating that it was stable. One of the four isolates was examined and found to be resistant also to narasin, salinomycin and lasalocid.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Drug Resistance, Microbial; Eimeria; Ionophores; Lasalocid; Monensin; Poultry Diseases; Pyrans

During the period from July 1977 to June 1985, specimens from 766 replacement layer and breeder chicken flocks were submitted to the Veterinary Research Institute, Victoria, Australia, for investigation of morbidity, mortality and, or, poor performance. A total of 5940 necropsies, as well as numerous ancillary tests, were performed. The findings for these flocks are presented and the consequences of some particular diseases noted.

Topics: Animals; Australia; Chickens; Dinitolmide; Female; Monensin; Nitrofurans; Poultry Diseases; Sulfaquinoxaline

Three experiments were conducted to evaluate the influence of several dietary factors on the monensin response in commercial broiler chicks fed corn-soybean meal diets varying in crude protein (CP). All experiments were conducted between 8 and 22 days posthatching. Trial 1 had a 2 X 2 X 2 factorial design wherein diets containing 16 or 24% CP and 0 or 121 mg/kg monensin were fed in the presence and absence of Eimeria acervulina infection. The monensin-induced growth depression was greater at 16% CP than at 24% CP. Coccidial infection had no effect on the monensin X protein level interaction. Monensin supplementation markedly improved performance of chicks infected with E. acervulina. Trial 2 was conducted to determine if the monensin-induced depression in performance caused by feeding a high level of monensin (140 mg/kg) could be moderated by feeding a high protein diet. Monensin supplementation reduced growth rate 18 and 10% in chicks fed 20 and 24% CP, respectively. Increasing CP to 28% alleviated the adverse effects of monensin on weight gain. Pair-feeding was used in Trial 3 to determine the extent to which the monensin-induced growth depression observed in chicks fed low protein diets was due to reduced feed intake. As expected, reducing the dietary CP from 24 to 16% resulted in a marked increase in the growth depression caused by 121 mg/kg monensin. Pair-feeding indicated that most of monensin's adverse effects in low protein diets could be attributed to its anorexic properties.

Topics: Animals; Body Weight; Chickens; Coccidiosis; Dietary Proteins; Feeding Behavior; Male; Monensin; Poultry Diseases

The influence of growth additives on the duration of salmonella shedding has been variously reported. The different conclusions reached were mainly because of the different experimental systems used. In this paper a naturally infected chicken model for evaluating this problem is described. It simulates commercial conditions and proved to be reproducible in 13 groups, each of 125 birds, over a two-year period.

Topics: Age Factors; Animals; Anti-Bacterial Agents; Cecum; Chickens; Cloaca; Female; Food Additives; Glycopeptides; Male; Monensin; Poultry Diseases; Salmonella; Salmonella Infections, Animal; Species Specificity

The effects of age vs. diet, potassium level, tetramethylthiuram disulfide (thiuram), and ionophores in the diet on the development of tibial dyschondroplasia in broilers was investigated. Changing broiler chicks from a diet that induced tibial dyschondroplasia to one that reduced the disease or vice versa caused a change in the incidence in the direction of the last-fed diet; however, in most cases the chicks did not develop as low or high an incidence of tibial dyschondroplasia as the birds fed the reducing or inducing diet, respectively, for the entire experimental period. Potassium supplementation of a corn-soybean meal diet that contained .88% potassium had no effect on the incidence of tibial dyschondroplasia. However, supplementation of a low potassium (.3%) corn-corn gluten meal-animal protein diet with potassium increased the incidence of tibial dyschondroplasia. The addition of thiuram to the diet caused an increase in tibial dyschondroplasia. When thiuram was added to the tibial dyschondroplasia-inducing diet, it also caused a decrease in bone ash and in the total and ultrafilterable plasma calcium. A significant negative correlation was obtained between incidence and score of tibial dyschondroplasia and bone ash of the ends and middles of the tibia when thiuram was fed. No consistent effects of the ionophores monensin and lasalocid on the development of tibial dyschondroplasia in broilers was noted in three experiments, although significant effects of the ionophores on the incidence or score of the disease was observed in two experiments.

Topics: Animals; Chickens; Diet; Lasalocid; Monensin; Osteochondrodysplasias; Potassium; Poultry Diseases; Thiram; Tibia

The development of resistance by the Houghton strain of Eimeria tenella (H) to monensin has been studied by serially passaging the strain in groups of 30 birds, each inoculated with 10(6) oocysts and given 100 p.p.m. of drug in the food. After 16 passages a line partially resistant to this concentration of monensin was produced. Passage of the line in birds medicated with 200 or 300 p.p.m. of monensin did not result in the acquisition of a greater degree of resistance. A further reduction in sensitivity to 100 p.p.m. monensin was obtained, however, when the line was serially passaged in 15 groups of 6 birds each given 3 X 10(6) oocysts. Five passages in the absence of monensin resulted in restoration of sensitivity, suggesting that the resistance developed was not stable. The pathogenic effects of the line that had been passaged in chickens given 300 p.p.m. of monensin were less than those of the parent line.

Topics: Animals; Cell Membrane; Chickens; Coccidiosis; Drug Resistance; Eimeria; Furans; Monensin; Poultry Diseases; Turkeys

The anticoccidial activity of CL 259,971, a new polyether ionophore produced by Actinomadura yumaense sp. nov, has been demonstrated against six species of poultry Eimeria, tested individually or in mixed species infections. Statistically significant activity was obtained against some species with as little as 2.5 ppm of drug. The optimal treatment level, however, was determined to be 5 ppm. At this level, performance was comparable to 100 or 120 ppm of monensin. CL 259,971 is coccidiocidal and affects the early asexual stages of the life cycle of E. tenella. Fed to uninoculated cockerels in batteries at 10 ppm for 7 weeks, CL 259,971 permitted numerically superior weight gains when compared with 200 ppm of monensin.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Ethers; Food Additives; Male; Monensin; Poultry Diseases; Safety; Species Specificity

Three floor-pen trials have confirmed the high anticoccidial activity of CL 259,971 as first reported in batteries. The optimal dosage level was shown to be 5 ppm in the diet. At this level, excellent anticoccidial activity was observed with no adverse effect on weight or performance. The results indicated that 5 ppm of CL 259,971 provided efficacy and performance comparable to arprinocid or monensin, which were used for comparison in these trials.

Topics: Adenine; Animal Feed; Animals; Body Weight; Chickens; Coccidiosis; Coccidiostats; Energy Metabolism; Ethers; Female; Food Additives; Male; Monensin; Poultry Diseases

In two experiments (Experiments A and B) chickens experimentally infected with S. infantis at 7 days of age and fed diets containing both avoparcin (10 ppm) and monensin (90 ppm) showed a higher frequency of Salmonella-positive livers and higher caecal counts of Salmonella 1 and 2 weeks after challenge than similarly infected chickens fed only avoparcin (10 ppm). The results may indicate a synergistic action between the two drugs on the ability of chickens to withstand Salmonella infections.

Topics: Animals; Anti-Bacterial Agents; Cecum; Chickens; Female; Food Additives; Furans; Glycopeptides; Liver; Male; Monensin; Poultry Diseases; Salmonella; Salmonella Infections, Animal

One hundred ninety-two male broiler chicks were dosed with monensin at concentrations of 0, 121, or 242 mg/kg feed throughout the normal growing period (50 days). Body weight gain and feed efficiency were determined weekly, and cardiac muscle was examined grossly and histologically at the end of the experiment. Livers also were weighed and examined grossly. Feed intake was determined daily, allowing continuous monitoring of drug intake. No depressing effects of the drug on growth rate and efficiency were observed until after four weeks, and then were evident only in the chicks receiving the 242 mg/kg diet. Subepicardial hemorrhage and congestion occurred in 40% of the hearts from the chickens fed the high monensin dose and were nonexistent in the other treatments. There appeared to be an inverse relationship between monensin dose and liver weight. The paralytic effects previously reported from acute dosing experiments were not observed. The results show that the heart and probably the liver are sensitive indicators of monensin toxicity and that the subchronic toxic dose is less than 18 mg/kg body weight per day.

Topics: Animal Feed; Animals; Chickens; Eating; Furans; Growth Disorders; Heart; Liver; Male; Monensin; Myocardium; Organ Size; Poultry Diseases

Healthy turkeys receiving 80 ppm monensin in their feed were injected at 26, 40 and 61 days of age with tiamulin at dosages of 12.5 and 25 mg/kg body weight. The aim of the study was to develop a regime for medicating with tiamulin turkeys receiving monensin in their feed, and which would circumvent the known toxicity created by the simultaneous administration of the two drugs. One injection of 12.5 mg/kg tiamulin up to the age of 61 days or 2 injections of 12.5 mg/kg tiamulin up to 40 days of age caused no mortality or adverse reaction.

Topics: Age Factors; Animal Feed; Animals; Anti-Bacterial Agents; Diterpenes; Drug Synergism; Furans; Growth Disorders; Injections, Intramuscular; Male; Monensin; Mycoplasma Infections; Poultry Diseases; Turkeys; Water

Five experiments were conducted with young, male, crossbred chicks to investigate the effects of experimental Eimeria acervulina infection on the efficacy of supplemental Cu and (or) methionine when added to a corn-soybean meal diet. Duodenal coccidiosis (due to E. acervulina) and supplemental Cu (500 and 750 mg/kg) depressed weight gain and efficiency of feed utilization. Supplemental Cu increased concentrations of Cu in liver and gallbladder; experimental coccidiosis resulted in a two- to fourfold increase in Cu deposition in these tissues compared with the respective controls. Excess supplemental methionine (.5%) had little effect on Cu toxicity in either healthy or infected chicks. Monensin, an ionophorous coccidiostat, alleviated the coccidiosis-induced Cu deposition.

Topics: Animal Feed; Animals; Body Weight; Chickens; Coccidiosis; Copper; Drug Interactions; Gallbladder; Liver; Male; Methionine; Monensin; Organ Size; Poultry Diseases

Chickens were given concentrations of monensin in the feed which increased at weekly intervals (60 to 121 ppm). This resulted in a fairly constant intake of drug (mg/k body weight). Such chickens consumed less drug than those given monensin at 121 ppm. Chickens given variable concentrations of drug in the food were well protected against coccidiosis judged by the parameters of lesion scores and mortality. Total body weight of these chickens was greater and lesion scores at 28 days were lower compared with chickens given constant levels of monensin, but the differences were not significant. These results suggest that adequate control of coccidiosis in broilers could be achieved by administering a relatively low concentration of an anticoccidial 0 to 3 weeks followed by a high concentration.

Topics: Administration, Oral; Animal Feed; Animals; Body Weight; Chickens; Coccidiosis; Furans; Male; Monensin; Poultry Diseases

Utilization of amino acids, sulfur-containing amino acid (SAA) in particular, is little affected by antibiotic and anticoccidial compounds. Coccidiosis (i.e., Eimeria acervulina infection) likewise seems to have little effect on SAA utilization. Copper sulfate, a commonly used antibacterial-antifungal compound (used at levels of 100-250 mg/kg diet), interacts with SAA. Hence, at upper levels of copper ingestion (i.e., 250 mg/kg and higher), copper binds SH compounds such as cysteine and reduced glutathione. Dietary SAA requirements are increased in both chicks and rats by dietary copper levels of 250 or 500 mg/kg. Hepatic copper deposition is enhanced by copper feeding and also by E. acervulina infection. These two effects, moreover, appear to be additive. The organic arsenic compound, roxarsone, interacts with SAA also, but in a different way. Thus, whereas added dietary cysteine partially ameliorates copper toxicity due to the binding of copper by cysteine-SH with subsequent excretion, roxarsone toxicity (i.e., 500 mg/kg diet) is exacerbated by supplemental cysteine.

Topics: Amino Acids; Amino Acids, Sulfur; Animals; Anti-Bacterial Agents; Arsenicals; Chickens; Coccidiosis; Coccidiostats; Copper; Lasalocid; Monensin; Poultry Diseases

The sensitivity of 32 field isolates of Eimeria acervulina to 100 ppm monensin was investigated in birds inoculated with 10(6) or 10(3) oocysts. Isolates were obtained from broiler farms where monensin had been used (broiler isolates) and from breeder farms where the drug had never been employed (breeder isolates). The drug was not completely effective against breeder isolates. When broiler and breeder isolates were compared, monensin was less effective against the former irrespective of whether weight gain or oocyst production was used to measure the infection. It is likely therefore that resistance to monensin may have been acquired as a result of its use in broiler chickens. The drug had activity against broiler isolates, however with more prolonged use, fully resistant strains may eventually emerge.

Topics: Animals; Animals, Newborn; Chickens; Coccidiosis; Drug Resistance; Eimeria; Furans; Monensin; Poultry Diseases

Topics: Animals; Chickens; Furans; Monensin; Poultry Diseases

Chickens treated at seven weeks of age with 150, 200, or 250 mg of crystalline monensin sodium/kg body weight had signs of toxicosis, including extreme weakness, anorexia, paralysis and death. Gross lesions included emaciation, generalized congestion, myocardial enlargement and pallor, and hydropericardium. Samples of ventricular myocardium, superficial pectoralis (white fibers), anterior latissimus dorsi (intermediate fibers), and sartorius muscles (mixed red, intermediate, and white fibers) were examined by light microscope. Intermyofibrillar vacuolation, histochemically positive for neutral fat, was severe in the myocardium and red muscle fibers and moderate in the intermediate muscle fibers. Myofiber necrosis was limited to the red muscle fibers. Mitochondrial degeneration was apparent in myocardial sections from several chickens. Interstitial infiltration by macrophages and heterophils was common in the myocardium and aerobic skeletal muscle.

Topics: Animals; Chickens; Furans; Male; Monensin; Muscles; Myocardium; Poultry Diseases

Topics: Animals; Anti-Bacterial Agents; Chickens; Coccidiosis; Coccidiostats; Drug Combinations; Eimeria; Ionophores; Lasalocid; Male; Monensin; Poultry Diseases; Pyrans

Hubbard breeder pullets were fed a complete pullet developer ration on an ad libitum (AL) or restricted feeding (RF) regimen. The ration either was unmedicated or contained .0125% amprolium, .0125% clopidol, or .0110% monensin. The relationship between the feeding schedule and coccidial infection was determined on the basis of 1) efficacy of the medication in controlling a single infection in susceptible pullets and 2) the development of immunity to subsequent challenge inoculation after a series of immunizing inoculations. Cage-reared, susceptible pullets were inoculated with sporulated oocysts of either. Eimeria tenella, 2 strains of E. acervulina, or E. maxima. With all three medications, the infection with a least one species was more severe, as measured by intestinal lesion score, in the RF pullets than in the corresponding AL pullets. Other pullets were kept for three weeks in floor pens that contained coccidial oocysts to allow natural infection and immunity to develop. The pullets were then transferred to suspended cages to prevent reinfection and fed an unmedicated ration. After one week, the pullets were challenged with the same coccidial strain as that used for immunizing. All pullets initially exposed to coccidia and given no medication were resistant to challenge inoculation. Control pullets are exposed to coccidia during rearing were susceptible to challenge. The administration of anticoccidial drugs (especially monensin) by ad libitum feeding interfered with development of immunity under these conditions, but, when the same drugs were given with a restricted feeding regimen, they did not interfere with development of immunity.

Topics: Animal Feed; Animals; Chickens; Clopidol; Coccidiosis; Female; Furans; Immunity; Monensin; Poultry Diseases; Pyridines

Topics: Animals; Chickens; Diterpenes; Drug Interactions; Furans; Monensin; Poultry Diseases

The efficacy of monensin at concentrations of 60 and 100 ppm was evaluated against 22 isolates not exposed to monensin and 16 monensin-exposed field isolates of coccidia obtained from US and Canadian turkey flocks, respectively. Isolates not previously exposed to monensin were effectively controlled by monensin. However, 7 monensin-resistant isolates (predominantly Eimeria meleagrimitis) were independently isolated from turkey flocks in Ontario, Canada where monensin was being used as an anticoccidial. Subsequent sensitivity evaluations of two of these isolates revealed cross-resistance to lasolocid, narasin, and salinomycin. Evaluation of the stability of monensin resistance in one isolate suggested that monensin sensitivity was not restored after 10 generations of relaxed selection. Although the extent of monensin resistance among field isolates of turkey coccidia is unknown, these results provide the first unequivocal characterization of monensin resistance in field isolates of coccidia. Contrarily, after more than eight years of intensive use of monensin as an anticoccidial in US broiler production facilities, this type of resistance to the polyether antibiotic anticoccidials has not been encountered in chicken coccidia.

Topics: Animals; Coccidiosis; Drug Resistance, Microbial; Eimeria; Furans; Monensin; Poultry Diseases; Turkeys

The discovery of monensin-resistant field isolates of Eimeria meleagrimitis prompted an investigation of the ability of this parasite to develop monensin resistance in a laboratory selection experiment. A strain derived from a monensin-sensitive parent strain was intentionally selected for monensin resistance by propagation in monensin medicated turkeys in isolation, while the monensin-sensitive parent strain from which it was derived was cryogenically maintained as a genetic control. Comparison of the monensin sensitivity of the selected and parent strains demonstrated monensin resistance development in the selected strain by the fourth generation of selection. This is the first reported experimental development of monensin-resistant coccidia and suggests that unlike chicken coccidia, the turkey coccidium E. meleagrimitis possesses the ability to readily develop resistance to the polyether antibiotic anticoccidials under the appropriate conditions of drug exposure.

Topics: Animals; Coccidiosis; Drug Resistance, Microbial; Eimeria; Furans; Monensin; Poultry Diseases; Turkeys

Lasalocid was tested at graded feed concentrations in controlled battery experiments against single and mixed Eimeria species infections in 2-week-old turykey poults. Eimeria meleagrimitis, E. gallopavonis, E. adenoeides, and E. dispersa infected poults medicated with lasalocid at concentrations of 0.15, .0125, .01, .0075, and .005% were heavier, converted feed more efficiently, showed lower lesion scores (ADI), shed fewer oocysts, and showed reduced or no mortality as compared to the infected, unmedicated controls. Lasalocid activity was similar against the few field isolates tested. Lasalocid responses were dose related, the higher the concentration, the greater the effect. The optimum dose level in these battery studies was approximately .0125%. Lasalocid fed at two times the optimum dose level to poults for a four week period did not have any adverse effect on growth or feed conversion performance.

Topics: Animals; Body Weight; Coccidiosis; Lasalocid; Monensin; Poultry Diseases; Turkeys

Three experiments were designed to test the efficacy of salinomycin and stenorol against infection by various Eimeria species on cage reared broiler type chicks. Efficacy was based on a coccidial index. Sixty parts per million salinomycin alone or in combination with 50 ppm 3 nitro significantly improved the index over basal treatments or when 3 nitro was used alone. The differences in index values recorded for coban and salinomycin were not significant. Stenorol significantly improved the index and appeared to be a most effective anticoccidial product. Broiler chickens reared in floor pens to 8 weeks showed a significant reduction in weight gain when the diet contained salinomycin +3 nitro or coban. Stenorol at 3, 6, or 9 ppm reduced body weight, with linear regression for this effect being highly significant (P less than .01). No coccidiosis was observed.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Ionophores; Male; Monensin; Piperidines; Poultry Diseases; Pyrans; Quinazolines; Quinazolinones; Roxarsone

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Furans; Ionophores; Lasalocid; Male; Monensin; Poultry Diseases; Pyrans

Topics: Animals; Anti-Bacterial Agents; Chickens; Coccidiosis; Coccidiostats; Furans; Lasalocid; Monensin; Poultry Diseases; Pyrans

The anticoccidial activities of monensin and lasalocid have been studied separately and in combination with tiamulin, a new pleuromutilin derivative. Combinations of constant tiamulin concentration (.0125%) in drinking water with various levels of polyether anticoccidials (6.3 to 125 ppm) in feed and conversely of constant levels of anticoccidials with various concentrations of tiamulin were used. The prophylactic efficacy of these combined treatments in battery raised broiler chickens infected with Eimeria tenella was evaluated. Assessment of the parameters mortality, weight gain, dropping scores, lesion scores, and oocyst output showed that simultaneous application of tiamulin significantly improved the anticoccidial activity of the polyethers. As tiamulin alone is without anticoccidial activity, this phenomenon was considered to result from an interaction between tiamulin and the polyethers leading to a slower metabolic degradation of the latter. Thus tissue levels adequate for maximum anticoccidial activity would be attained with lower polyether dose levels. Experiments using isolated perfused rat liver showed that elimination of monensin was reduced by 60% in the presence of tiamulin.

Topics: Animals; Anti-Bacterial Agents; Chickens; Coccidiosis; Coccidiostats; Diterpenes; Drug Synergism; Drug Therapy, Combination; Female; In Vitro Techniques; Lasalocid; Liver; Monensin; Poultry Diseases; Rats

Bacteria-free chicks in separate plastic film isolators were inoculated orally with single species of bacteria. Within an isolator, half the birds were fed unmedicated feed and half received feed containing 100 ppm monensin. With clostridium perfringens as the established species of monoflora, bacterial counts from the duodenum were 10(4) times lower and counts from the ceca were three times lower in monensin-fed birds compared to unmedicated birds. Infection with Eimeria tenella stimulated an eight-fold increase in the numbers of C. perfringens in the ceca of unmedicated birds but no increase in monensin-fed birds. With Bacteroides sp. or Streptococcus faecalis as monoflora, there was no difference in the cecal or duodenal populations between medicated and unmedicated birds uninfected with coccidia. In contrast to C. perfringens, populations of Bacteroides sp. and S. faecalis in the ceca decreased five to 100-fold in both medicated and unmedicated chicks after infection with E. tenella. Duodenal populations of C. perfringens, Bacteroides sp., and S. faecalis were unaffected by the coccidial infection.

Topics: Animals; Bacteria; Bacteroides; Cecum; Chickens; Clostridium perfringens; Coccidiosis; Duodenum; Enterococcus faecalis; Furans; Germ-Free Life; Monensin; Poultry Diseases

Groups of 33 chickens were fed continuously on diets containing feed additives that are employed commercially for a variety of purposes, and were infected orally when 4 days old with a nalidixic acid-resistant mutant of Salmonella typhimurium. The amount of S. typhimurium organisms excreted in their faeces was estimated by culturing them at intervals and in a standard manner on brilliant green agar containing sodium nalidixate; when the chickens were killed their caecal contents were examined by the same technique.Avoparcin and lincomycin, like nitrovin and tylosin (Smith & Tucker, 1975b), favoured colonization of the alimentary tract by the S. typhimurium organisms as shown by the fact that the chickens to which they were fed excreted these organisms in their faeces in higher concentration and for longer periods of time than did chickens fed on non-medicated diets. Amprolium, monensin, dimetridazole, arsenilic acid and nitro-hydroxyphenylarsonate had no obvious effect on the salmonella excretion pattern.When only five chickens in each group were experimentally infected so that the effect of the feed additives on infections acquired by contact could be monitored, avoparcin, lincomycin, nitrovin and tylosin again favoured colonization of the alimentary tract with the S. typhimurium organisms and so did dimetridazole. Arsenilic acid, in contrast, hindered the development of infection. Amprolium, monensin and nitro-hydroxyphenylarsonate were without obvious effect.Many of the chickens that were fed on diets that favoured S. typhimurium colonization, but not those fed on non-medicated diets, were still excreting S. typhimurium organisms in their faeces when they were killed at 56 days of age, the age at which broiler chickens kept under commercial conditions are usually slaughtered.

Topics: Amprolium; Animal Feed; Animals; Anti-Bacterial Agents; Arsenicals; Chickens; Digestive System; Dimetridazole; Feces; Glycopeptides; Leucomycins; Lincomycin; Monensin; Nitrovin; Poultry Diseases; Salmonella typhimurium

Monensin, fed in excess of 200 ppm caused mortality in Triple 5 and Triple 6 turkeys aged 25 weeks old and over. Mortality commenced three to four days after administering feed containing monensin and ceased three to five days after it was removed. This concentration of drug did not have any detectable adverse effects on Triple 5 turkeys fed from day old, four weeks old, or 11 weeks old for periods of two weeks.

Topics: Animal Feed; Animals; Furans; Monensin; Poultry Diseases; Turkeys

Topics: Animals; Furans; Monensin; Poultry Diseases; Turkeys

Topics: Animals; Chickens; Coccidiosis; Furans; Monensin; Paralysis; Poultry Diseases

Lonomycin (TM-481, SQ 12,525) at various concentrations in the feed was tested in controlled battery experiments against laboratory strains of single and mixed Eimeria species infections. The experimental results indicated that lonomycin at doses of .003125, .00625, or .0125% demonstrated a high degree of anticoccidial activity by preventing or reducing mortality, reducing fecal dropping scores, and allowing for normal or near-normal weight gains against single and mixed infections of 5 major pathogenic species, E. acervulina, E. brunetti, E. maxima, E. necatrix, and E. tenella. Lonomycin, at these same dosages, was highly effective against a recent field isolate obtained from a flock previously fed monensin. These studies involving 7 trials totaling 1,680 broiler chicks, have demonstrated that lonomycin at levels of .003125 to .0125% (dependent on species of Eimeria) in the feed is an effective aid in the control of avian coccidiosis in broiler chickens.

Topics: Administration, Oral; Animal Feed; Animals; Anti-Bacterial Agents; Body Weight; Chickens; Coccidiosis; Coccidiostats; Ethers; Female; Lasalocid; Male; Monensin; Nigericin; Poultry Diseases

Feed medication with monensin caused delays in development of immunity in two floor-pen experiments which simulated commercial broiler production. Development of immunity was retarded with the higher level of monensin (120 p.p.m.) but was progressively less delayed as the monensin level was decreased (100, 60 or 0 p.p.m.). Delay was greatest with Eimeria tenella, but also occured with intestinal species including E. acervulina, E. brunetti, E. maxima, E. mivati, and E. necatrix. Drug withdrawal permitted earlier development of immunity. Plans involving use of monensin on layer replacements which later will be maintained on the floor without medication should consider: 1) prevalence of infective oocyst exposure in the area, 2) the lowest possible level of drug required for protection, and 3) its use for the shortest possible period of time.

Topics: Administration, Oral; Animal Feed; Animals; Chickens; Coccidiosis; Female; Furans; Monensin; Poultry Diseases

Infections with single species of Eimeria acervulina, E. mivati, E. maxima, E. tenella, E. necatrix, and E. brunetti, and the six species mixed, were utilized in three separate battery experiments to evaluate the anticoccidial efficacy of various levels of salinomycin (AHR-3096), a fermentation product of a strain of Streptomyces albus. At the 60 to 100 p.p.m. treatment levels, this compound showed significant anticoccidial activity for all parameters studied (mortality, weight gain, feed conversion, dropping scores, and lesion scores). The mortality due to coccidiosis was reduced to 0.1% in the medicated infected birds. Some activity, as measured by weight gain, was seen in the lower levels of salinomycin medication (12.5 to 50 p.p.m.), but other parameters, including mortality and lesion scores, indicated less activity than that seen with the higher treatment levels. At 100 p.p.m., there was no apparent effect on the compound on bird performance in uninfected control birds. Salinomycin at the 100 p.p.m. treatment level was statistically as effective as 121 p.p.m. monensin (reference anticoccidial) in controlling coccidiosis.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Body Weight; Chickens; Coccidiosis; Coccidiostats; Intestines; Monensin; Poultry Diseases; Pyrans

The anticoccidial activity of lasalocid, monensin, and roxarsone, alone and in combination, was evaluated against eleven Eimeria tenella recent field isolates. Lasalocid was used at 0.0075. 0.01, and 0.0125% activity drug in feed; monensin at 0.0099 and 0.0121%; and roxarsone at 0.005%. Further studies with lasalocid 0.0075%, monensin 0.0099% and roxarsone 0.005 and 0.0025% combinations were carried out against three E. tenella field isolates selected from the aforementioned strains. Lasalocid and monensin each exhibited a high degree of anticoccidial activity at all concentrations tested. Lasalocid and monensin fed in combination with roxarsone showed, in addition to high anticoccidial activity a further reduction in gross lesions and oocysts production, more pronounced at 0.005% level of roxarsone than at 0.0025%, compared to either medication alone or the roxarsone combinations. These positive effects were noted with all strains tested. The practical aspects of these findings are discussed.

Topics: Administration, Oral; Animal Feed; Animals; Anti-Bacterial Agents; Arsenicals; Chickens; Coccidiosis; Drug Combinations; Feces; Female; Furans; Lasalocid; Male; Monensin; Poultry Diseases; Roxarsone

The anticoccidial efficacy, host tolerance, and projected resistance development of the three polyether antibiotics, monensin, narasin, and lasalocid were compared. The efficacy of narasin against different coccidial strains was found to parallel that of monensin in as much as strains which were refractory to monensin were also refractory to narasin. In contrast, lasalocid easily controlled some strains which were not well controlled by either narasin or monensin and failed to control one strain readily controlled by these two antibiotics. In growing chicks, lasalocid at the projected use level of 75 p.p.m. and narasin at an efficacious level of 100 p.p.m. were both better tolerated than monensin at the recommended use level of 121 p.p.m. The frequency of mutants resistant to each of these polyether compounds was found to be less than 8.6 X 10(-9) per drug sensitive oocyst for one strain of Eimeria tenella. This corresponds to less than 0.036 and 0.148 as frequent as mutants of this strain resistant to glycarbylamide or to amquinate, respectively.

Topics: Animals; Anti-Bacterial Agents; Chickens; Coccidiosis; Drug Resistance; Feces; Female; Furans; Lasalocid; Male; Monensin; Mutation; Poultry Diseases; Pyrans

Three experiments determined if the methionine requirement of broiler chicks was affected by coccidial infection. Chicks were fed a corn-soy or a corn-soy-pea basal diet containing 0.73% and 0.62% total sulfur amino acids (TSAA), respectively. Levels of 0 to 0.45% DL-methionine were added, with and without 0.01% monensin sodium. In two experiments, the chicks were inoculated at two weeks of age with a mixture of oocysts of E. acervulina, E. maxima, E. tenella, E. necatrix and E. brunetti. Lesion scores on the intestines and ceca, and blood carotenoid levels were determined at three weeks. The experiments were terminated at four weeks. A level of methionine greater than 0.47% and of TSAA greater than 0.83% was necessary to obtain maximum growth rate in uninoculated chicks. No evidence of dermatitis was observed. Growth rate and feed efficiency of chicks infected with coccidiosis were more severly depressed when the diet was not supplemented with methionine. Infections of coccidia and low levels of methionine, which in themselves did not produce any significant change in weight gain, did give a significant weight depression in combination. Adding monensin to the diet prevented a reduction in growth rate and feed efficiency of inoculated chicks fed adequate methionine. Monensin did not completely prevent the adverse effects of a coccidial infection, based on feed efficiency, when chicks were fed diets inadequate in methionine. Blood carotenoid levels were not affected by methionine level, but were significantly lowered by coccidial infection in the absence of monensin. Intestinal and cecal lesions in inoculated chicks were significantly reduced by including monesin in the diet. Although the coccidial infection more severly affected the performance of chicks fed diets deficient in methionine, satistical analysis of pooled data indicated no difference in the quantitative requirement of chicks for methionine. Therefore, a level of methionine and cystine adequate for optimum growth under the coccidial-free conditions should be adequate for chicks when infected with coccidia.

Topics: Animals; Body Weight; Carotenoids; Chickens; Coccidiosis; Cystine; Methionine; Monensin; Poultry Diseases

The feed level of monensin which gave maximal protection from coccidial infection in broilers reared in floor pens depended on the severity of the coccidial exposure and the criteria of infection studied. With indirect seeding of pens with coccidia (light coccidial exposure), 40 ppm was as efficacious as 100 ppm in improving weight gain, lesion score, and feed conversion. Statistical analysis with direct seeding (seeder birds; severe coccidial exposure) showed that feed levels of 84 and 102 ppm gave maximal improvement of weight gain and 4-week feed conversion, respectively. Further increasing the monensin level from 100 to 121 ppm did not improve weight gain and feed conversion at 8 weeks. Conversely, the relationship of plasma pigmentation and total lesion scores to monensin feed levels indicated that increasing the dosage of monensin from 100 to 121 ppm improved the performance of the broilers on the basis of these 2 infection indicators.

Topics: Administration, Oral; Animal Feed; Animals; Body Weight; Carotenoids; Chickens; Coccidiosis; Female; Furans; Male; Monensin; Poultry Diseases; Skin Pigmentation

In a series of nine experiments birds subjected to heat-stress showed decreases of 9 to 61 percent in feed intake. In only one of these experiments, involving E. acervulina and monensin, was there sufficient reduction of anticoccidial intake to partially nullify effects of drug protection. In this case, a 40 percent decrease in monensin intake resulted in significantly higher lesion scores (1.9 vs. 1.0) (P less than or equal to 0.05) in birds maintained at 32 C. for days 1 to 7 postinfection (P.I.) compared to controls maintained at 20C. No other failures due to heat stress occurred with this anticoccidial in three other trials with E. acervulina or or five trials involving E. tenella infection. In one experiment E. tenella coccidiosis (lesion scores 0.7 vs. 1.1) was more severe in the cool environment than in birds under heat-stress from 2 to 7 days P.I. Similarly, less severe lesions of E tenella (0.4 vs. 0.8) occurred during heat-stress (32 C) than in controls maintained at 11 C. in zoalene-fed and unmedicated control birds. No differences in lesion scores occurred in birds in hot versus cool room environments in two experiments involving sulfaquinoxaline or one with robenidene and E. tenella infection. E tenella lesions inunmedicated controls were significantly more severe in the cool than the hot environment in one experiment. Results from these experiments suggest that decreases in feed and anticoccidial intake during heat-stress could seldom be the cause of coccidiosis breaks under field conditions.

Topics: Animals; Chickens; Coccidiosis; Hot Temperature; Male; Monensin; Poultry Diseases

Monensin was effective within the range 60-100 p.p.m. in control of coccidiosis in turkey poults in a series of laboratory experiments. Under conditions of heavy infections with Eimeria meleagrimitis and E. adenoides, 100 p.p.m. of monesin was significantly more effective than 60 p.p.m. in protecting weight gains. When light or moderate infections with E. meleagrimitis, E. adenoides and E. gallopavonis were used, there were no significant differences among monesin-medicated treatments. In all instances the monensin-medicated treatments gained significantly more weight than noninfected, nonmedicated controls, when measured at 7 days post-inoculation. Similarly, oocyst, passage was reduced, feed conversion was protected and mortality was controlled in monensin-treated poults.

Topics: Animals; Body Weight; Coccidiosis; Feces; Furans; Monensin; Poultry Diseases; Turkeys

The activities of monensin, lasalocid and halofuginone against Eimeria tenella, E. brunetti and E. necatrix have been studied under laboratory conditions. Complete control of experimental infections in the chick, separable from toxicity, was not obtained with monensin, but was achieved with the other two compounds at levels of 150 and 6 ppm in the food respectively. All three compounds appear to inhibit coccidial development very early in the life-cycle, and to have a fairly rapid lethal effect, monensin and lasalocid more so than the febrifugine derivative. In vivo observations have been supplemented with in vitro studies. Some discussion of the difficulties of relating laboratory experiments to field performance is given.

Topics: Administration, Oral; Animal Feed; Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Feces; Lasalocid; Monensin; Piperidines; Poultry Diseases; Quinazolines; Quinazolinones