diclazuril and Poultry-Diseases

The study was conducted to consider the anticoccidial and immunogenic effectivities of encapsulated organic acids and anticoccidial drugs in broilers reared on a reused litter infected with Eimeria spp. for simulating in-field exposure to avian coccidiosis. 525 mixed-sex one-day-old broiler chicks (Ross 308) were used in a 2 × 3 factorial experiment as a completely randomized design with seven experimental groups and five replicates of 15 chicks. The seven experimental groups were included: negative (uninfected; T

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Lactones; Nitriles; Organic Chemicals; Poultry Diseases; Triazines

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

The effect of diclazuril medication on the development of natural immunity to Eimeria tenella was determined. Birds in two treatments, nonexposed, non-challenged (NENC) and nonexposed, challenged (NEC), were from a holding group raised under conditions designed to prevent coccidial infection. Birds in five other treatments, from the same hatch and source as birds in the first two treatments, were from a floor pen study involving a natural exposure to Eimeria spp. These birds were assigned to the current study based on their respective treatments in the original floor pen study as follows: unmedicated (UNM), 66 ppm salinomycin (SAL) + 50 ppm roxarsone in the starter and grower diets to Day 28 (SAL 28), 66 ppm SAL + 50 ppm roxarsone in the starter diet and 1 ppm diclazuril (DIC) in the grower diet to Day 28 (DIC 28) or to Day 35 (DIC 35), or in the grower and finisher diets to Day 42 (DIC 42). Each treatment comprised three floor pens of 10 birds (female) in a randomized complete block design. All birds were fed an UNM finisher diet during the 7-d challenge study. Birds in each treatment, except NENC, were individually inoculated (p.o.) with 1 x 10(5) Eimeria tenella sporulated oocysts on Day 1. Based on bird performance and cecal lesion scores, birds in the DIC 35 and 42 treatments had a low immunity to the challenge infection, birds in the DIC 28 treatment were partially immunized, and the highest levels of immunity were observed in the UNM and SAL 28 treatments.

Topics: Animal Nutritional Physiological Phenomena; Animals; Chickens; Coccidiosis; Coccidiostats; Diet; Eimeria tenella; Female; Immunity, Innate; Nitriles; Poultry Diseases; Triazines; Weight Gain

A 49-d floor pen study was conducted with broiler chickens to compare the effects of different anticoccidial withdrawal times on the efficacy of 1 ppm diclazuril. The starter diet in three treatments contained 66 ppm salinomycin + 50 ppm roxarsone (3-nitro-4-hydroxyphenylarsonic acid), followed by 1 ppm diclazuril in the grower diet commencing on Day 17. Diclazuril was withdrawn from these treatments on Day 28, 35, or 42 (finisher diet), respectively. Two other treatments in the study were given 66 ppm salinomycin + 50 ppm roxarsone in the starter and grower diets to Day 28 or no anticoccidial (unmedicated). The starter (Days 0 to 16), grower (Days 17 to 35), and finisher (Days 36 to 49) diets in each treatment included 55 ppm bacitracin methylene disalicylate for growth promotion. Fifty 1-d-old chicks were randomly allotted to each of 10 pens per treatment using a randomized complete block design. Birds in each pen were raised on litter naturally contaminated with a mixture of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. The results demonstrated that some performance loss occurred in the salinomycin Day 28 treatment. Means for weight gain and feed conversion on Day 49 were improved (P < 0.05) in each diclazuril treatment in comparison with the salinomycin and unmedicated treatments. Feed conversion means in the diclazuril Day 35 and Day 42 treatments were improved (P < 0.05) in comparison with the diclazuril Day 28 treatment, indicating that shorter withdrawal times provided further benefit.

Topics: Aging; Animal Nutritional Physiological Phenomena; Animals; Chickens; Coccidiosis; Coccidiostats; Diet; Eimeria; Housing, Animal; Nitriles; Parasite Egg Count; Poultry Diseases; Pyrans; Triazines; Weight Gain

To clarify the character of the anticoccidial activity of diclazuril a series of battery trials was conducted. Diclazuril showed excellent anticoccidial activity in the infection of chickens with Eimeria tenella, E. necatrix or E. acervulina at the feeding level of 0.1 ppm. When diclazuril was administered in combination with a nucleic acid precursor, uracil, uridine, orotate or orotidine, the reduction of the activity of diclazuril to the infections induced by above species was not observed. While, bloody droppings with severe cecal lesions were resulted, when diclazuril was administered in combination with uridine 5(1)-diphosphoglucose (UDPG) or its N-acetyl amine (UDPGNAC) to chickens infected with E. tenella. While, body weight gain of the birds and oocyst output was not affected by these combination-treatment. Results demonstrated that the antagonistic effect of UDPG and UDPGNAC to diclazuril was partial. The possibility of the cross resistance between diclazuril and 6-azauracil (AzU) in E. tenella was investigated using two populations induced resistance to AzU or diclazuril. The results demonstrated that the cross resistance does not exist between AzU and diclazuril, indicating that the mode of action of each drug is different.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Drug Interactions; Drug Resistance; Eimeria; Nitriles; Nucleic Acid Precursors; Orotic Acid; Poultry Diseases; Triazines; Uracil; Uridine; Uridine Diphosphate Glucose; Uridine Diphosphate N-Acetylglucosamine

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

This study aimed to determine the potential prophylactic efficacy of probiotic individually and/or in combination with anti-coccidial drug on the performance and immunity of broilers under an induced coccidial infection over a 28-day of experimental trial.. One hundred and eighty 1-day-old Cobb broiler chicks were randomly divided into five groups, included control group (CG), control positive group (CPG), probiotic-treated group (Prob), diclazuril-treated group (Dic), and probiotic + diclazuril-treated group (Prob + Dic). On day 21 of age, all birds, except group CG, were orally inoculated with 1 ml of tap water containing 25,000 Eimeria tenella sporulated oocysts.. Our results showed that the probiotic treatment did not influence pre-challenge body weight, feed intake and feed conversion ratio (FCR). During the post-challenge period, chickens in groups probiotic and diclazuril individually and in combination exhibited higher body weight and lower (better) FCR, reduced oocyst shedding (throughout the day four, five, six and seven post-infection), cecal lesions and mortality compared with control positive chickens. Moreover, Compared to CPG group, Prob + Dic group showed increased (p < 0.05) serum levels of interleukin-10 (IL-10) and immunoglobulin M (IgM) and decreased the concentrations of interferon gamma (IFN-γ). On the other hand, individual treatment with probiotic exhibited highest serum levels of IL-10 and IgM, while diclazuril alone increased the blood concentrations of IL-10 and decreased the levels of IFN-γ compared to control positive group; however, there was no significant effect of Prob on IFN-γ, Dic on IgM and all groups on interleukin-17.. In conclusion, supplementation of probiotic, with and/or without anti-coccidial drug, enhances immunity and inhibits the negative effects of Eimeria infection.. This study reveals the anti-coccidial mechanisms of probiotic in the presence and absence of anti-coccidial drug in preventing the coccidia infection.

Topics: Animal Feed; Animals; Chickens; Coccidiosis; Diet; Eimeria; Nitriles; Poultry Diseases; Probiotics; Triazines

Diclazuril (DIC) is widely used in the poultry industry to control coccidiosis. However, drug resistance makes it less effective, and the underlying mechanism remains unclear. One DIC-resistant E. tenella (RE) isolate and one sensitive E. tenella (SE) isolate were used to compare the differences in their endogenous development, pathogenicity, invasion-related gene expression and apoptotic characteristics. Chickens were allocated into four groups to receive RE or SE strain and their corresponding DIC treatment or not. Caeca tissues were sampled at 96 h, 120 h and 144 h post-infection (PI) for pathological analysis. Meanwhile, second-generation merozoites (Mz2) were separated at 120 h PI to detect alterations in mitochondrial membrane potential (MMP), apoptotic rate and caspase-3 activity and mRNA expression of protein phosphatase 5 (PP5), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), actin depolymerizing factor (ADF) and microneme proteins (MICs). Haematoxylin and eosin staining revealed that DIC treatment strictly blocked the development of the SE strain but slightly affected the RE strain. Meanwhile, the number of SE Mz2 and their MMP decreased at the same time the apoptotic rate increased after DIC treatment. Real-time quantitative PCR and caspase-3 activity studies demonstrated that Mz2 from the RE strain had higher mRNA expression of ADF and MICs along with no significant changes in GAPDH and caspase-3 activity under DIC pressure compared to its control; in contrast, the mRNA expression of ADF, MICs and PP5 was markedly suppressed in Mz2 from SE with upregulated caspase-3 activity and GAPDH transcription. In addition, the mRNA expression of GAPDH and PP5 in Mz2 from RE was remarkably higher than that of SE. Taken together, the higher mRNA expression of invasion-related genes and almost unaffected endogenous development provide a better understanding of coccidian resistance to DIC.

Topics: Animals; Caspase 3; Chickens; Coccidiosis; Eimeria tenella; Glyceraldehyde-3-Phosphate Dehydrogenases; Nitriles; Poultry Diseases; RNA, Messenger; Triazines

Toxoplasma gondii is a widespread zoonotic protozoan that infects most species of mammals and birds, including poultry. This study aimed to investigate the course of T. gondii infection and the efficacy of diclazuril and Artemisia annua in preventing infection in experimentally infected chickens. Seventy-five 1-month-old chickens, female and male, were randomly divided into five groups (n = 15 each) as follows: (1) uninfected untreated (negative control, NC); (2) infected with T. gondii genotype II/III isolated from a wild cat (group WC); (3) infected with T. gondii genotype II isolated from a domestic cat (group DC); (4) infected with T. gondii domestic cat strain and treated with the anticoccidial diclazuril (group DC-D); and (5) infected with T. gondii domestic cat strain and treated with the medicinal plant Artemisia annua (group DC-A). Clinical signs, body temperature, mortality rate, weight gain, feed conversion ratio, hematological parameters, and the presence of T. gondii-specific IgY antibodies were recorded in all groups. Five chickens per group were euthanized 28 days post-infection (p.i.) and their brains, hearts, and breast muscle tested for T. gondii by mouse bioassay and polymerase chain reaction (PCR). No clinical signs related to the experimental infection were observed throughout the study period. T. gondii-specific antibodies were detected by day 28 p.i., but not in all infected chickens. Overall, T. gondii DNA was detected (bioassay or tissue digests) in all infected and untreated chickens (10/10), while viable parasite (bioassay) was isolated from 7 out of 10 chickens. The parasite was most frequently identified in the brain (7/10). There were no differences in the T. gondii strains regarding clinical infection and the rate of T. gondii detection in tissues. However, higher antibody titers were obtained in chickens infected with T. gondii WC strain (1:192) comparing with T. gondii DC strain (1:48). A. annua reduced replication of the parasite in 3 out of 5 chickens, while diclazuril did not. In conclusion, broiler chickens were resistant to clinical toxoplasmosis, irrespective of the strain (domestic or wild cat strain). The herb A. annua presented prophylactic efficacy by reduced parasite replication. However, further studies are required aiming at the efficacy of diclazuril and A. annua for the prevention of T. gondii infection in chickens using quantitative analysis methods.

Topics: Animals; Antibodies, Protozoan; Artemisia annua; Brain; Cats; Chickens; Coccidiostats; Female; Genotype; Heart; Male; Mice; Nitriles; Pectoralis Muscles; Plants, Medicinal; Poultry Diseases; Random Allocation; Seroconversion; Tissue Distribution; Toxoplasma; Toxoplasmosis, Animal; Triazines

Chicken coccidiosis, caused by an obligate intracellular protozoan parasite of the genus Eimeria, is a major parasitic disease in the intensively reared poultry industry. Due to the widespread use of anticoccidial drugs, resistance has become an inevitable problem. In our previous study, Eimeria tenella citrate synthase (EtCS) was found to be up-expressed in two drug-resistant strains (diclazuril-resistant and maduramycin-resistant strains) compared to drug-sensitive strain by RNA sequence. In this study, we cloned and expressed EtCS and obtain its polyclonal antibodies. Quantitative real-time polymerase chain (qPCR) reactions and Western blots were used to analyze the transcription and translation levels of EtCS in sensitive and three drug-resistant strains. Compared with the sensitive strain, the transcription of EtCS was both significantly upregulated in diclazuril-resistant and maduramycin-resistant strains, but was not significantly different in salinomycin-resistant strain. No significant difference was seen in translation level in the three drug-resistant strains. Indirect immunofluorescence indicated that EtCS was mainly located in the cytoplasm of sporozoites except for posterior refractile bodies and in the cytoplasm and surface of merozoites. Anti-rEtCS antibody has inhibitory effects on E. tenella sporozoite invasion of DF-1 cells and the inhibition rate is more than 83%. Binding of the protein to chicken macrophage (HD11) cells was confirmed by immunofluorescence assays. When macrophages were treated with rEtCS, secretion of nitric oxide and cell proliferation of the macrophages were substantially reduced. These results showed that EtCS may be related to host cell invasion of E. tenella and involve in the development of E.tenella resistance to some drugs.

Topics: Amino Acid Sequence; Animals; Antibodies, Protozoan; Base Sequence; Blotting, Western; Chickens; Citrate (si)-Synthase; Cloning, Molecular; Coccidiosis; Eimeria tenella; Fluorescent Antibody Technique, Indirect; Immune Sera; Macrophages; Merozoites; Mice; Nitric Oxide; Nitriles; Poultry Diseases; Pyrans; Rabbits; Real-Time Polymerase Chain Reaction; Specific Pathogen-Free Organisms; Sporozoites; Triazines

Avian coccidiosis is a widespread and economically significant disease in poultry. At present, treatment of coccidiosis mainly relies on drugs. Anticoccidial drugs can be divided into two categories: ionophorous compounds and synthetic drugs. However, the emergence of drug-resistant strains has become a challenge for coccidiosis control with anticoccidial drugs. To gain insights into the molecular mechanism governing the drug resistance of Eimeria tenella, two drug-resistant strains of E. tenella, one maduramicin-resistant (MRR) strain and one diclazuril-resistant (DZR) strain, were generated. We carried out comparative transcriptome analyses of a drug-sensitive strain (DS) and two drug-resistant MRR and DZR strains of E. tenella using RNA-sequencing. A total of 1,070 differentially expressed genes (DEGs), 672 upregulated and 398 downregulated, were identified in MRR vs. DS, and 379 DEGs, 330 upregulated and 49 downregulated, were detected in DZR vs. DS. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed to better understand the functions of these DEGs. In the comparison of DZR vs. DS, some DEGs were involved in peroxisome, biosynthesis of unsaturated fatty acids, and fatty acid metabolism. In the comparison of MRR vs. DS, some DEGs were involved in glycolysis/gluconeogenesis, regulation of actin cytoskeleton, and DNA replication. In addition, some DEGs coded for surface antigens that were downregulated in two drug-resistant strains involved invasion, pathogenesis, and host-parasite interactions. These results provided suggestions for further research toward unraveling the molecular mechanisms of drug resistance in Eimeria species and contribute to developing rapid molecular methods to detect resistance to these drugs in Eimeria species in poultry.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria tenella; Exome Sequencing; Feces; Gene Expression Profiling; Gene Expression Regulation; Gene Regulatory Networks; Lactones; Nitriles; Poultry Diseases; Protozoan Proteins; Sequence Analysis, RNA; Triazines

The study was conducted to investigate the combination of a probiotic strain of Enterococcus faecium and diclazuril to control coccidiosis in broilers.. A total of 240 one-day-old female broiler chicks were divided into eight groups (30 chicks per group): prophylactic groups (G1, G2 and G3) and therapeutic groups (G4, G5 and G6) and two control groups (untreated infected, G7 and untreated uninfected, G8 controls). In the prophylactic approach, diclazuril alone (G1), probiotic alone (G2) or a mixture of both probiotic and diclazuril (G3) was orally administered to the chicks via drinking water 10 days prior to the infection. However, in the therapeutic approach, G4, G5 and G6 birds were administered diclazuril alone, probiotic alone and diclazuril+probiotic mix, respectively, in drinking water for five consecutive days after the appearance of clinical signs of coccidiosis. Birds of both approaches and G7 were experimentally infected with 25 × 10. The probiotic supplementation as a prophylactic approach can decrease the adverse effects of eimerian infection. In addition, the probiotic and diclazuril mix achieved a considerable improvement in the growth performance. Therefore, probiotic plus diclazuril combination achieved a synergistic effect.. Investigation into the synergism/antagonism between a probiotic and diclazuril as anticoccidial agent and the difference in the timing of administration.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Enterococcus faecium; Female; Nitriles; Oocysts; Poultry Diseases; Probiotics; Triazines; Weight Gain

Coccidiosis is a crucial parasitic disease of the poultry industry. As a result of the enormous global economic losses and the increased resistance to the conventional anticoccidial agents, there is a continuous need to find new anticoccidials. Here, the anticoccidial effect of the fluoroquinolone lomefloxacin versus diclazuril in experimentally infected broilers was tested for the treatment of Eimeria tenella infection. Ninety 14-day-old Cobb strain broiler chickens were allocated into five groups, each with 18 chicks. Group 1 (G1) was separated as an uninfected negative control and received no treatment; group 2 (G2), infected untreated (positive control); group 3 (G3), infected and treated with lomefloxacin at a dose rate of 100 ppm in drinking water; group 4 (G4), infected and treated with diclazuril at a dose rate of 2.5 ppm in drinking water; group 5 (G5), infected and treated with lomefloxacin at a dose rate of 100 ppm plus diclazuril at dose rate of 2.5 ppm in drinking water. Clinical signs, mortality rates, number of oocysts per gram of faeces (OPG), growth performance parameters (weight gain: WG and feed conversion ratio: FCR), lesion scoring, haematological and serum biochemical analyses, antioxidant biomarkers and histopathologic inspection of the caeca were used as evaluation criteria for the anticoccidial efficacy of both lomefloxacin and diclazuril. The findings herein showed that administration of lomefloxacin and/or diclazuril improved growth performance parameters (WG, FCR) and significantly (P ≤ 0.05) reduced OPG, and diminished the severity of bloody diarrhoea and mortalities. Additionally, haematological indices and serum biochemical parameters such as ALT, AST, ALP, creatinine, uric acid, total proteins, albumin and globulin were improved. Finally, a significant elevation in the levels of the antioxidant biomarkers was observed in the chicks of G3, G4 and G5 as compared with those of G2.

Topics: Animals; Cecum; Chickens; Coccidiosis; Coccidiostats; Eimeria tenella; Feces; Fluoroquinolones; Nitriles; Oocysts; Poultry Diseases; Triazines; Weight Gain

Decoquinate (DQ) is used for prophylaxis against coccidian infections within the digestive tract of chickens, but DQ is extremely insoluble in water. Hence, improving the water solubility of DQ is extremely important. First, decoquinate nanoliposomes (DQNLs) were prepared by the thin-film dispersion-ultrasonic method. The preparation conditions of DQNLs were optimized using the orthogonal test. The optimal preparation conditions of DQNLs were: a ratio of egg-yolk lecithin:drug (w/w) of 10:1, ratio of egg-yolk lecithin:cholesterol (w/w) of 5:1, rotary-evaporation temperature of 50 ℃, and ultrasound duration of 15 min. The encapsulation efficiency of DQNLs prepared under these conditions reached 99.24 % and drug loading was 5.67 %. The characterization of optimized DQNLs was also done. Transmission electron microscopy of DQNLs showed that they had the characteristic structure of liposomes. The mean particle size was 115.6 nm. The polydispersity index was 0.175. The zeta potential was -39.1 mV. The stability of DQNLs was high upon storage at 4 ℃. In vivo studies demonstrated that the lower dose (5 mg/L) of DQNLs in drinking water obtained the similar anticoccidial efficacy to that of 40 mg/kg DQ in feed against diclazuril-resistance Eimeria tenella isolate. The in vitro inhibitory effect of DQNLs on the sporulation of Eimeria tenella oocysts was dose-dependent. Therefore, the anticoccidial efficacy of DQ was enhanced significantly after being encapsulated into nanoliposomes.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Decoquinate; Drug Resistance; Liposomes; Nitriles; Poultry Diseases; Triazines

Eimeria tenella is an obligate intracellular parasite of the chicken cecum; it brings huge economic loss to the chicken industry. Enolase is a multifunctional glycolytic enzyme involved in many processes of parasites, such as infection and migration. In this study, the effect of diclazuril on the expression of enolase in second-generation merozoites of E. tenella (EtENO) was reported. The prokaryotic expression plasmid pET-28a-EtENO was constructed and transformed into Escherichia coli BL21 (DE3). Then, it was subjected to expression under the induction of isopropyl-β-D-1-thiogalactopyranoside. The expressed products were identified and purified. The purified EtENO protein was used for antibody preparation. The EtENO mRNA and protein expression levels were analyzed via real-time PCR and Western blotting. Localization of EtENO on the merozoites was examined by immunofluorescence technique. The mRNA and protein expression levels of EtENO were decreased by 36.3 and 40.36%, respectively, by diclazuril treatment. EtENO distributed in the surface, cytoplasm, and nucleus of the infected/control group. With diclazuril treatment, it was significantly reduced in the surface and cytoplasm and even disappeared in the nucleus of the infected/diclazuril group. These observations suggested that EtENO may play an important role in mechanism of diclazuril anticoccidial action and be a potential drug target for the intervention with E. tenella infection.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria tenella; Gene Expression Regulation, Enzymologic; Merozoites; Nitriles; Phosphopyruvate Hydratase; Poultry Diseases; Triazines

Diclazuril, which is widely used for the prevention of coccidiosis in chickens, has a lethal effect on asexual and sexual stages of Eimeria spp. However, little is known about its effect on the exogenous stages of Eimeria spp. In this study, we evaluated the effect of in vitro treatment with 0.2% diclazuril on unsporulated and sporulated oocysts of Eimeria spp. For this purpose, a total of 180 male layer chicks aged one day were randomly divided into 5 experimental groups. Each group was divided into 3 replicates of 12 chicks each. Group 1 (G1) and Group 2 (G2) were negative (non-immunized and non-challenged) and positive (non-immunized and challenged) controls, respectively. Group 3 (G3) was immunized per os with 1.0 × 10

Topics: Animals; Cecum; Chickens; Coccidiosis; Eimeria; Male; Nitriles; Oocysts; Poultry Diseases; Random Allocation; Triazines; Virulence

Eimeria tenella, an obligate intracellular parasite, can actively invade the cecal epithelial cells of chickens and cause severe enteric disease. Eukaryotic elongation factor 2 (eEF2) plays a major role in protein synthesis and cell survival. This study aims to explore the exact mechanisms underlying diclazuril inhibition in second-generation merozoites of E. tenella. The eEF2 cDNA of the second-generation merozoites of E. tenella (EtEF2) was cloned by reverse transcriptase polymerase chain reaction and rapid amplification of cDNA ends. Diclazuril-induced expression profiles of EtEF2 were also analyzed. The cloned full-length cDNA (2893 bp) of the EtEF2 nucleotide sequence encompassed a 2499 bp open reading frame (ORF) that encoded a polypeptide of 832 residues with an estimated molecular mass of 93.12 kDa and a theoretical isoelectric point of 5.99. The EtEF2 nucleotide sequence was submitted to the GenBank database with the accession number KF188423. The EtEF2 protein sequence shared 99 % homology with the eEF2 sequence of Toxoplasma gondii (GenBank XP_002367778.1). The GTPase activity domain and ADP-ribosylation domain were conserved signature sequences of the eEF2 gene family. The changes in the transcriptional and translational levels of EtEF2 were detected through quantitative real-time PCR and Western blot analyses. The mRNA expression level of EtEF2 was 2.706 fold increases and the protein level of EtEF2 was increased 67.31 % under diclazuril treatment. In addition, the localization of EtEF2 was investigated through immunofluorescence assay. Experimental results demonstrated that EtEF2 was distributed primarily in the cytoplasm of second-generation merozoites, and its fluorescence intensity was enhanced after diclazuril treatment. These findings indicated that EtEF2 may have an important role in understanding the signaling mechanism underlying the anticoccidial action of diclazuril and could be a promising target for novel drug exploration.

Topics: Amino Acid Sequence; Animals; Base Sequence; Blotting, Western; Chickens; Coccidiosis; Coccidiostats; Eimeria tenella; Elongation Factor 2 Kinase; Female; Fluorescent Antibody Technique; Male; Merozoites; Mice; Mice, Inbred BALB C; Nitriles; Phylogeny; Poultry Diseases; Real-Time Polymerase Chain Reaction; Sequence Alignment; Triazines

The objective of present studies was to evaluate and compare the anticoccidial activity of triazine compounds in broiler chickens infected with E. tenella, E. necatrix, E. acervulina, E. maxima, and two field mixed Eimeria species. The anticoccidial efficacy was evaluated using the anticoccidial index (ACI). The results showed that Aminomizuril (AZL) and Ethanamizuril (EZL) were active metabolites of nitromezuril, which demonstrated excellent effectiveness against E. tenella, E. necatrix, E. acervulina, E. maxima, and the field Eimeria isolates in broiler chickens at a dosage of 10 mg/kg in feed. The anticoccidial activities of AZL and EZL at dose 10 mg/kg were roughly equivalent to the parent nitromezuril at a dosage of 3 mg/kg in feed. The decrease in metabolite anticoccidial activity is probably due to an increasing polarity of compounds in the metabolic processes. The sensitivity of two field Eimeria isolates to triazines EZL, diclazuril and toltrazuril was tested using 4 indices including anticoccidial index (ACI), percent of optimum anticoccidial activity (POAA), reduction of lesion scores (RLS) and relative oocysts production (ROP). Results showed that the sensitivity of EZL treatment against the two field Eimeria isolates were relatively superior to that of diclazuril and toltrazuril treatment. The field Eimeria isolates from Gansu Province was determined to be slightly, moderately and highly resistant to EZL, diclazuril and toltrazuril respectively. The field Eimeria isolates from Zhejiang Province was slightly, highly and slightly resistant to EZL, diclazuril and toltrazuril respectively. The results above indicated that the anticoccidial activity of metabolites was lower than that of the parent nitromezuril and there was partial cross-resistance among triazines EZL, diclazuril and toltrazuril. However the field Eimeria isolates had higher sensitive to EZL than the triazines diclazuril and toltrazuril. It was suggested that the site of C4 substituents of phenol of triazine anticoccidials may have important biological functions and the metabolite EZL would be a potential novel anticoccidial agent worthy of more attention.

Topics: Animals; Chickens; Coccidiosis; Drug Resistance; Eimeria; Nitriles; Oocysts; Poultry Diseases; Triazines

Anticoccidial sensitivity tests (ASTs) serve to determine the efficacy of anticoccidial drugs against Eimeria field isolates in a controlled laboratory setting. The most commonly measured parameters are body weight gain, feed conversion ratio, gross intestinal lesion scores, and mortality. Due to the difficulty in reliably scoring gross lesion scores of Eimeria maxima , microscopic analysis of intestinal scrapings (microscores) can be used in the field to indicate the presence of this particular Eimeria. The goal of this study was to determine the relationship between E. maxima microscores and broiler body weights and gross E. maxima lesion scores in three ASTs. Day-old broiler chicks were raised for 12 days on a standard corn-soy diet. On Day 12, chicks were placed in Petersime batteries and treatment diets were provided. There were six birds per pen, four pens per treatment, and 12 treatments, for a total of 288 chicks per AST. The treatments were as follows: 1) nonmedicated, noninfected; 2) nonmedicated, infected; 3) lasalocid, infected; 4) salinomycin, infected; 5) diclazuril, infected; 6) monensin, infected; 7) decoquinate, infected; 8) narasin + nicarbazin, infected; 9) narasin, infected; 10) nicarbazin, infected; 11) robenidine, infected; and 12) zoalene, infected. On Day 14, chicks were challenged with an Eimeria field isolate by oral gavage. On Day 20, broilers were weighed, and gross lesion scores and microscores were classified from 0 to 4 depending on the severity of the gross lesion scores and E. maxima microscores. Data from three trials using different field isolates were statistically analyzed using a logarithmic regression model. There was no relationship (P = 0.1224) between microscores and body weight gain. There was a positive relationship between microscores and gross lesion scores (P = 0.004). However, there was also an interaction between isolate and treatment (P < 0.0001). Lastly, the interaction between isolate and gross lesion scores (P = 0.0041) demonstrates that the significance of the relationship between microscores and gross lesion scores may be dependent on pathogenicity of the challenge Eimeria or the amount of E. maxima in the inoculum.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Nitriles; Poultry Diseases; Pyrans; Triazines; Weight Gain

An experiment was conducted to determine the effects of oregano essential oil on growth performance and coccidiosis prevention in mild challenged broilers. A total of 250 1-d-old chicks were used in a completely randomized design with 5 treatments and 5 replicates with 10 birds in each replication. Experimental treatments included: (1) negative control (NC; unchallenged), (2) positive control (PC; challenged with sporulated oocysts of Eimeria), (3) PC fed 200 ppm Diclazuril in diet, (4) PC fed 300 ppm oregano oil in diet, and (5) PC fed 500 ppm oregano oil in diet. At 22 d of age, all the experimental groups except for NC were challenged with 50-fold dose of Livacox T as a trivalent live attenuated coccidiosis vaccine. On d 28, two birds were slaughtered and intestinal coccidiosis lesions were scored 0-4. Moreover, dropping was scored in the scale of 0-3, and oocysts per gram feces (OPG) were measured. Oregano oil at either supplementation rate increased body weight gain (P=0.039) and improved feed conversion ratio (P=0.010) from d 22 to 28, when compared with PC group. Using 500 ppm oregano oil in challenged broilers diet increased European efficiency factor than PC group (P=0.020). Moreover, challenged broilers fed 500 ppm oregano oil or Diclazuril in diets displayed lower coccidiosis lesions scores in upper (P=0.003) and middle (P=0.018) regions of intestine than PC group, with the effect being similar to unchallenged birds. In general, challenged birds fed 500 ppm oregano oil or Diclazuril in diets had lower OPG (P=0.001), dropping scores (P=0.001), litter scores (P=0.001), and pH of litter (P=0.001) than PC group. It could be concluded that supplementation of oregano oil at the dose of 500 ppm in diet may have beneficial effect on prevention of coccidiosis in broilers.

Topics: Animal Feed; Animals; Chickens; Coccidiosis; Coccidiostats; Diet; Dietary Fats, Unsaturated; Dietary Supplements; Eimeria; Female; Male; Nitriles; Oils, Volatile; Origanum; Poultry Diseases; Triazines

The effects of diclazuril on the bursa of Fabricius (BF) structure and secretory IgA (SIgA) expression in chickens infected with Eimeria tenella were examined. The morphology of the BF was observed by hematoxylin and eosin staining, while ultrastructural changes were monitored by transmission electron microscopy. E. tenella infection caused the BF cell volumes to decrease, irregularly arranged, as well as, enlargement of the intercellular space. Diclazuril treatment alleviated the physical signs of damages associated with E. tenella infection. The SIgA expression in BF was analyzed by immunohistochemistry technique. The SIgA expression increased significantly by 350.4% (P<0.01) after E. tenella infection compared to the normal control group. With the treatment of diclazuril, the SIgA was relatively fewer in the cortex, and the expression level was significantly decreased by 46.7% (P<0.01) compared with the infected and untreated group. In conclusion, E. tenella infection in chickens induced obvious harmful changes in BF morphological structure and stimulated the expression of SIgA in the BF. Diclazuril treatment effectively alleviated the morphological changes. This result demonstrates a method to develop an immunological strategy in coccidiosis control.

Topics: Animals; Bursa of Fabricius; Chickens; Coccidiosis; Coccidiostats; Eimeria tenella; Female; Immunoglobulin A, Secretory; Male; Nitriles; Poultry Diseases; Triazines

Secretory immunoglobulin A (SIgA), as a vital actor involving in the mucosal immunity, plays a key role in defending a variety of pathogenic infections, such as bacteria, viruses and parasites. Eimeria tenella is an obligate intracellular apicomplexan parasite contacting with the digestive tract mucosa and specially parasitizes chicken caecum, causing a severe form of coccidiosis. Coccidiosis is currently mainly controlled using chemotherapeutic agents. Diclazuril, a classic coccidiostat, was used widely in the poultry industry. Because of the rising problem of drug resistance, it is therefore crucial to understand the pattern of the SIgA expression in the action of diclazuril against E. tenella. In this study, the intestinal morphology in the caecum was analyzed by haematoxylin-eosin (HE) staining, and the SIgA expression was examined by immunohistochemical technique. At the same time, the duodenum, jejunum and ileum tissues have also been evaluated. HE staining results showed that E. tenella infection caused severe damage characterized by structural disorder, haemorrhage, inflammatory cell infiltration, serous and fibrinous exudation in chicken caecum and invisible damage in the duodenum, jejunum and ileum. With the treatment of diclazuril, the damage in the caecum was alleviated obviously. Immunohistochemical analysis demonstrated that the SIgA level in the infected group was increased in the duodenum (p < 0.05), jejunum and ileum, respectively, but decreased (p < 0.01) in the caecum, compared with the control group. Interestingly, the SIgA level was decreased in the duodenum (p < 0.05), jejunum and ileum but increased (p < 0.05) in the caecum in the infected/diclazuril group in comparison to the infected group. The results showed that diclazuril effectively alleviated the damage in the caecum induced by E. tenella and provided a cure for coccidiosis by improving the immune function in chickens.

Topics: Animals; Cecum; Chickens; Coccidiosis; Coccidiostats; Eimeria tenella; Immunity, Mucosal; Immunoglobulin A, Secretory; Intestines; Male; Nitriles; Poultry Diseases; Random Allocation; Triazines

This study investigated the effects of various coccidiosis control programs in combination with antibiotic growth promoters (AGPs) on growth performance and host immune responses in broiler chickens. The coccidiosis programs that were investigated included in ovo coccidiosis vaccination (CVAC) with Inovocox or in-feed medication with diclazuril as Clinacox (CLIN) or salinomycin (SAL). The AGPs were virginiamycin or bacitracin methylene disalicylate plus roxarsone. As a negative control, chickens were non-vaccinated and fed with non-supplemented diets (NONE). All animals were exposed to used litter from a commercial broiler farm with confirmed contamination by Eimeria parasites to simulate in-field exposure to avian coccidiosis. Broiler body weights in the CVAC group were greater at 14 and 32 days of age, but not at day 42, compared with the NONE, CLIN, and SAL groups. At day 14, the SAL group showed decreased body weight and reduced ConA-stimulated spleen cell proliferation compared with the CLIN and SAL groups. In contrast, at days 34 and 43, splenocyte proliferation was greater in the CVAC and CLIN groups compared with the NONE and SAL groups. Lymphocyte subpopulations and cytokine mRNA expression levels in the intestine and spleen were also altered by the denoted treatments. Collectively, these results suggest that in ovo coccidiosis vaccination or coccidiostat drug medication programs in combination with AGPs influences chicken growth and immune status in an Eimeria-contaminated environment.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Chick Embryo; Chickens; Coccidiosis; Coccidiostats; Cytokines; Eimeria; Gene Expression Regulation; Male; Nitriles; Poultry Diseases; Protozoan Vaccines; Pyrans; RNA, Messenger; Spleen; Triazines

Diclazuril, a benzeneacetonitrile anticoccidial agent, has potent activity against various stages of Eimeria tenella (E. tenella). To study the effects of diclazuril on E. tenella merozoites, purified second-generation merozoites were obtained from infected chicken caecal tissue at 120h after inoculation by a combination of enzymatic digestion, centrifugation, erythrocytes disruption and percoll density gradient centrifugation. Ultrastructural changes were monitored by transmission electron microscopy (TEM). Apoptosis and mitochondrial transmembrane potential were determined by flow cytometry (FCM). The results showed that diclazuril induced ultrastructural changes and significantly increased the ratio of early apoptosis by 180.75% (P<0.01) and late apoptosis/necrosis by 86.82% (P<0.05) in second-generation merozoites, respectively. Compared with the infected/control group, the ratio of second-generation merozoites that lost mitochondrial function was increased by 45.04% (P<0.01) in the infected/treatment group. In conclusion, diclazuril induced morphological changes and attenuated the activity of mitochondrial transmembrane potential of merozoites, which is involved in mitochondrial-depended apoptosis in second-generation merozoites of E. tenella.

Topics: Animals; Apoptosis; Chickens; Coccidiosis; Coccidiostats; Eimeria tenella; Male; Membrane Potentials; Merozoites; Mitochondria; Nitriles; Poultry Diseases; Random Allocation; Triazines

The effects of diclazuril on mRNA expression levels of invasion-related microneme genes were examined in second-generation merozoites of Eimeria tenella (E. tenella) by quantitative real-time (QRT) PCR. Diclazruil treatment of infected chickens significantly decreased the number of second-generation merozoites by 65.13%, and resulted in downregulation of EtMIC genes: EtMIC1 by 65.63%, EtMIC2 by 64.12%, EtMIC3 by 56.82%, EtMIC4 by 73.48%, and EtMIC5 by 78.17%. SEM images of caecum tissue from uninfected chickens showed regular intestinal villus structure. In infected chickens, a distinct loss of the superficial epithelium, with a flattened mucosa and large-area necrosis and anabrosis, was evident. In diclazruil-treated chickens, a decrease in merozoite number and a visibly improved appearance of the caeca were noted. These improvements appeared to be mediated in part by downregulation of the expression of invasion-related EtMIC genes in response to diclazuril.

Topics: Animals; Cecum; Chickens; Coccidiosis; Coccidiostats; DNA, Complementary; Eimeria tenella; Gene Expression; Glycoproteins; Male; Merozoites; Microscopy, Electron, Scanning; Nitriles; Polymerase Chain Reaction; Poultry Diseases; Protozoan Proteins; Random Allocation; RNA, Protozoan; Triazines

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Dose-Response Relationship, Drug; Intestinal Absorption; Male; Nitriles; Poultry Diseases; Regression Analysis; Triazines; Xylose

The efficacy and economic benefits of Supercox, a live anticoccidial vaccine were examined and compared with an anticoccidial drug in a trial in broiler chickens under modern commercial conditions in China. In total, 40,660 chickens were used in the present study, half of which were vaccinated with the Supercox vaccine comprising a precocious line of Eimeria tenella and non-attenuated lines of Eimeria maxima and Eimeria acervulina, and the other half were medicated with Diclazuril delivered as feed additive at the dosage of 1mg/kg of feed. The vaccine was administered orally to 7-day-old chickens. No clinical diseases were diagnosed in any of the vaccinated birds. However, clinical coccidiosis occurred in a large proportion of medicated control birds and these chickens had to be treated with anticoccidial drugs (Diclazuril and Toltrazuril). Comparison of production performance between vaccinated birds and medicated control birds revealed that the vaccine Supercox performed better than anticoccidial drugs in terms of mortalities, costs and overall economic benefits (profits). These findings demonstrated that the use of the Supercox vaccine could control clinical coccidiosis in broilers and achieve production performance superior to that using anticoccidial drugs, particularly where drug resistance might result in failure to control clinical diseases.

Topics: Animals; Chickens; China; Coccidiosis; Coccidiostats; Cost-Benefit Analysis; Feces; Female; Male; Nitriles; Parasite Egg Count; Poultry Diseases; Protozoan Vaccines; Random Allocation; Treatment Outcome; Triazines; Vaccination

Prophylactic and curative capacity of water soluble formulation of Diclazuril (Diclosol 1%) and feed additive form (Clinacox, 0.5%) were tested against Eimeria infection in broiler chickens. Such testing was performed both experimentally and in the field. Toltrazuril (Baycox, 2.5%) was used as reference control drug. Water soluble formulation of Diclazuril induced a marked inhibitory effect on the different stages of the parasite life cycle in experimentally infected treated birds especially when applied on the day when blood first appeared in the faeces [fifth day post-infection (d.p.i.)] as well as on the second day of blood dropping (6 d.p.i.). Both tested dosage levels of Diclazuril water soluble formulation in drinking water (5 and 10 ppm) showed the same effect in controlling coccidial infection and reducing the total oocyst numbers, lesion and faecal scores. Moreover, there was no significant difference in the efficacy of water soluble form of Diclazuril and the reference control drug (Toltrazuril, 25 ppm). In addition, testing the water soluble formulation (5 ppm) in naturally infected poultry farm (20,000 birds), showed the same anticoccidial effect observed when using Toltrazuril, as a treatment for coccidiosis. In conclusion, addition of Diclazuril at the dose of 5 ppm in the drinking water of naturally coccidia infected bird induced the same effect as 25 ppm of Toltrazuril as a treatment for coccidiosis in chickens.

Topics: Administration, Oral; Animals; Chickens; Coccidiosis; Coccidiostats; Drinking; Nitriles; Poultry Diseases; Random Allocation; Solubility; Treatment Outcome; Triazines

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

Two 42-d floor pen studies were conducted with commercial broiler chickens to measure the efficacy of 1 ppm diclazuril in the starter or grower diet in shuttle programs with 66 ppm salinomycin. Study 1 compared a salinomycin to diclazuril (starter to grower diet) shuttle treatment with salinomycin to salinomycin, salinomycin to 100 ppm monensin, salinomycin to 99.8 ppm lasalocid, and unmedicated treatments. Study 2 compared a diclazuril to salinomycin (starter to grower) shuttle treatment with 125 ppm nicarbazin to salinomycin, 79.2 ppm narasin + nicarbazin to salinomycin, 125 ppm zoalene to salinomycin, and unmedicated treatments. Fifty 1-d-old chicks were randomly allotted to each of 10 pens per treatment in each study using a randomized complete block design. Starter (Days 0 to 21) and grower (Days 22 to 37) diets in each study contained 55 ppm bacitracin methylene disalicylate. The finisher diet (Days 38 to 42) in each study was unmedicated. Birds were inoculated via their feed on Day 22 (Study 1) or Day 15 (Study 2) with a mixed inoculum of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Four birds per pen (two male and two female) were randomly selected in each study for coccidial lesion scores on Day 6 postinoculation. These studies demonstrated that the use of 1 ppm diclazuril in shuttle programs was highly efficacious against a mixed inoculum of Eimeria spp. in comparison with nicarbazin, narasin + nicarbazin, and zoalene in starter diets and salinomycin, monensin, and lasalocid in grower diets.

Topics: Animal Feed; Animal Husbandry; Animals; Chickens; Coccidiosis; Coccidiostats; Eimeria; Female; Housing, Animal; Ionophores; Male; Nitriles; Poultry Diseases; Triazines; Weight Gain

Three battery tests were conducted to study the anticryptosporidial efficacy of the 2 commercially available anticoccidial triazinone derivates, diclazuril and toltrazuril, and a garlic extract. At the recommended level, diclazuril reduced the oocyst output of birds by 14.6%. The efficacy of toltrazuril was 52.1% at the recommended level, which could be moderately increased using 5 or 10 times the recommended dose. However, these doses resulted in significant weight gain reduction. The efficacy of garlic extract was 24.4%. It is concluded that none of the drugs can be recommended for chemoprophylaxis or therapy of cryptosporidiosis in chickens.

Topics: Animals; Chickens; Coccidiostats; Cryptosporidiosis; Feces; Garlic; Male; Nitriles; Phytotherapy; Plant Extracts; Plants, Medicinal; Poultry Diseases; Triazines; Weight Gain

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

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

The effect of diclazuril, fed to chickens at 1 ppm in the feed, was studied to determine whether the drug interfered with the development of immunity to Eimeria tenella. Group A was not treated, Groups B and C received diclazuril from Day 1 until Day 15, after which time the medicated feed was replaced by blank feed for the remainder of the experiment from Day 16 until Day 42. Immunization was performed in Groups A and B by artificial trickle infections with 2,000 sporulated oocysts per bird on Days 4, 6, 8, 11, and 13. On Day 29, a challenge infection was given using 200,000 oocysts per bird. The unmedicated birds (Group A) developed subclinical coccidiosis after the trickle infections with excretion of oocysts and a slightly decreased growth performance. At challenge, a good protective unimmunity was present, reflected by a good growth performance and a low oocyst excretion. The unimmunized birds (Group C) developed a severe clinical disease after challenge with high oocyst output, increased mortality, and poor growth performance. The diclazuril-medicated, trickle-infected birds (Group B) were well protected, both against the immunizing trickle infections and the challenge infection. After challenge, no clinical disease developed, although some lesions and oocyst excretion were present. It is concluded that, under the conditions of the trial, diclazuril did not significantly interfere with protective immunity formation against E. tenella.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Immunity, Active; Nitriles; Poultry Diseases; Triazines; Weight Gain

Diclazuril is a benzeneacetonitrile showing great promise as a broad-spectrum anticoccidial agent for chickens, turkeys, and rabbits. The high anticoccidial activity of diclazuril in chickens, as first reported in dose-titration studies and battery trials, was confirmed in three floor-pen trials. The efficacy was demonstrated against six major pathogenic species of Eimeria after artificial infection with one or more species. The experimental data indicated that diclazuril, at dose levels of .5, .75, 1, and 2 ppm, had a high anticoccidial activity in terms of preventing mortality, suppressing or reducing lesion scores, and allowing for normal weight gains as well as productivity. The performances obtained with diclazuril was generally comparable with that of salinomycin at 60 ppm and that of lasalocid at 90 ppm.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Female; Male; Nitriles; Poultry Diseases; Triazines

Resistance to diclazuril was induced by 10 passages of the Houghton strains of Eimeria acervulina and E. tenella in chickens given progressively greater concentrations of the drug. This resistance was, however, not complete since the drug retained some efficacy against the drug-passaged lines. Attempts to passage the Houghton strain of E. maxima in birds medicated with concentrations of diclazuril greater than 0.016 parts per million (ppm) were unsuccessful and after 10 passages at this concentration resistance had not developed. Resistance to methyl benzoquate developed after 6 passages of E. tenella in medicated chickens but resistance to amprolium was only partial after 10 passages. The pathogenicity of diclazuril- and amprolium-resistant lines of E. tenella was lower than that of the parental line. Diclazuril was effective against lines of E. tenella resistant to amprolium, arprinocid, clopidol, dinitolmide, halofuginone, methyl benzoquate, monensin and robenidine.

Topics: Amprolium; Animals; Chickens; Coccidiosis; Coccidiostats; Drug Resistance; Eimeria; Nitriles; Poultry Diseases; Quinolones; Triazines

Diclazuril, a new anticoccidial drug, was tested in poultry against six Eimeria species either in single species infections in dose titration studies or in mixed species infections in floor pen trials. The dose titration studies in cockerels indicated that diclazuril at dosages of 10, 5, 1, and .5 ppm was highly active against all major pathogenic species: E. tenella, E. acervulina, E. necatrix, E. brunetti, E. maxima, and E. mitis and effective in terms of weight gain and suppression of mortality, dropping scores, and oocyst counts. In two floor pen trials diclazuril was fed for 6 wk to broiler chickens experimentally infected either with E. tenella and E. acervulina or with E. necatrix and E. brunetti. Dose levels of 10, 5, and 1 ppm suppressed mortality and lesion scores. Even at 1 ppm the mean terminal body weight, feed conversion, and productivity index of treated birds were comparable to results for the uninfected, unmediated controls. In these pilot studies, involving 1,020 Hisex and 1,000 Hubbard broiler chickens, it has been demonstrated that diclazuril at the dose level of 1 ppm in the diet is an excellent anticoccidial without any adverse effects.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Dose-Response Relationship, Drug; Eimeria; Male; Nitriles; Poultry Diseases; Triazines; Weight Gain

Battery trials have confirmed the broad spectrum anticoccidial activity of diclazuril as previously reported in dose titration studies. The advocated dose level of 1 ppm in the diet demonstrated excellent activity against the economically most important Eimeria species. At this dose level, body weight gains were comparable to those of uninfected, unmedicated controls and the oocyst production was negative in most species. Lesion scores and dropping scores were nil or highly reduced. An E. maxima-147 strain, less sensitive to ionophores, also responded well to diclazuril. It was concluded that diclazuril is a promising anticoccidial for the control of all species of coccidia that cause losses to the poultry industry.

Topics: Animals; Chickens; Coccidiosis; Coccidiostats; Male; Nitriles; Poultry Diseases; Triazines; Weight Gain

The ultrastructural morphology of the different endogenous stages of Eimeria maxima and E. brunetti was evaluated after oral treatment of inoculated chickens with a single dose of 5 mg/kg diclazuril. The drug induced no ultrastructural change in the growth or differentiation of the various schizont stages of both Eimeria spp. In E. maxima, the micromorphological appearance of micro- and macrogamonts developing from the blast from to maturation also remained unaffected by drug treatment. However, in all fertilized macrogamonts the normal pattern of oocyst wall establishment was completely disturbed, resulting in the formation of an abnormally thickened, incomplete oocyst wall and the necrosis of the zygote. In E. brunetti, the growth and nuclear division during microgametogenesis were not affected but differentiation was clearly abnormal. In comparison with the controls, this abnormal differentiation was characterized by a less extensive enlargement of the parasite surface area, aberrant morphological configurations of condensed heterochromatin, intracytoplasmic flagella formation, and glycogen accumulation. Finally, the complete degeneration of all microgamonts ensued. The growth and differentiation leading to mature macrogamonts was not disturbed; however, subsequent oocyst wall formation was largely precluded and the macrogamonts proceeded to degenerate completely. We conclude that diclazuril treatment primarily affected particular stages in the sexual development of both Eimeria spp., resulting in the complete eradication of these coccidian species.

Topics: Animals; Cell Wall; Chickens; Coccidiosis; Coccidiostats; Eimeria; Nitriles; Poultry Diseases; Species Specificity; Triazines

Diclazuril, a new benzeneacetonitrile anticoccidial, has potent activity against various stages of Eimeria tenella. A single treatment of experimentally infected chickens during the prepatent phase (up to day 5) results in a complete interruption of the life cycle and oocyst shedding. The first- and second-generation schizonts show extensive degenerative changes that finally result in a complete loss of the parasitic stage. The degeneration is characterized by loss of internal structure, the appearance of many intracytoplasmic vacuoles, and incomplete merogony. The merozoites themselves show similar degenerative changes, including the presence of numerous small vacuoles in the cytoplasm. Diclazuril is also effective against both the micro- and macrogametocytes that have a ballooned appearance and loose their internal structure completely. In the macrogametocytes, wall-forming bodies either do not develop or disappear rapidly. Development of typical caecal lesions is prevented when treatment with diclazuril is initiated before large numbers of second-generation schizonts appear, i.e., day 3. It is concluded that diclazuril is lethal against both the asexual and the sexual stages of E. tenella. At the proposed use level of 1 ppm in the feed, the life cycle is interrupted at a very early stage and lesion development and oocyst shedding are completely prevented.

Topics: Animals; Cecum; Chickens; Coccidiosis; Coccidiostats; Eimeria; Intestines; Male; Nitriles; Poultry Diseases; Triazines

A single 5-mg/kg oral dose of diclazuril affected both the asexual and sexual development of Eimeria tenella in experimentally inoculated chickens. In second-generation schizonts, early growth and nuclear divisions progressed normally, but a marked inhibition of merozoite formation was observed. Exogenesis of merozoites was largely prevented, whereas production of micronemes, amylopectin granules, and dense bodies and the formation of rhoptries, conoid, and pellicle continued. All these subcellular organelles accumulated, together with differentiated nuclei, within the main cytoplasmic mass. In the end, complete necrosis of the schizonts occurred. In macrogamonts, dilation of the rough endoplasmic reticulum around type II wall-forming bodies, fusion of type II wall-forming body contents, disturbance of the normal parallel arrangement of rough endoplasmic reticulum, and disruption of row formation of amylopectin granules became evident. In the microgamonts, normal evagination of microgametes was prevented; the flagellar complex formed within the main cytoplasmic mass and the differentiated nuclei remained present within the parasite body. The macro- and microgamonts also ended up in a stage of complete necrosis. These data indicate that diclazuril treatment primarily affects the normal differentiation of the respective endogenous stages during parasite development. This leads to complete degeneration of schizonts and gamonts indicating the lethal effect of this new anticoccidial compound.

Topics: Animals; Cell Nucleus; Chickens; Coccidiosis; Coccidiostats; Cytoplasm; Eimeria; Microscopy, Electron; Nitriles; Poultry Diseases; Triazines