lasalocid and narasin

Two experiments were designed to evaluate the impacts of supplementing lasalocid (LAS), narasin (NAR), or virginiamycin (VRM) on rumen fermentation parameters, apparent nutrient digestibility, and blood parameters (Exp. 1), as well as feed intake and performance (Exp. 2) of Nellore cattle consuming a forage-based diet. In Exp. 1, 32 rumen-fistulated Nellore steers (initial shrunk body weight [BW] = 355 ± 4.4 kg) were assigned to a randomized complete block design. Within block, animals were randomly assigned to one of four treatments: 1) forage-based diet without feed additives (CON), 2) CON diet plus 13 mg/kg of dry matter (DM) of NAR, 3) CON diet plus 20 mg/kg of DM of sodium LAS, or 4) CON diet plus 20 mg/kg of DM of VRM. No treatment effects were detected (P ≥ 0.32) for intake and apparent digestibility of nutrients. Steers fed NAR had the lowest (P ≤ 0.01) molar proportion of acetate on day 28, 56, and 112 vs. CON, LAS, and VRM steers, whereas acetate did not differ (P ≥ 0.25) between LAS, VRM, and CON steers from day 28 to 84. On day 112, steers fed LAS had a lower (P < 0.02) molar proportion of acetate vs. VRM and CON, whereas it did not differ between CON and VRM (P > 0.33). Steers receiving NAR had a greater (P ≤ 0.04) ruminal propionate vs. CON, LAS, and VRM, whereas LAS steers had greater (P < 0.04) propionate vs. CON and VRM steers on day 28 and 112, and it did not differ (P > 0.22) between CON and VRM. In Exp. 2, 160 Nellore bulls were blocked by initial shrunk BW (212 ± 3.1 kg) in a 140-d feedlot trial. Diets contained the same treatments used in Exp. 1. Bulls fed NAR had greater (P < 0.02) average daily gain (ADG) vs. CON and VRM, and similar (P = 0.17) ADG between NAR and LAS, whereas ADG did not differ (P > 0.28) between LAS, VRM, and CON bulls. A treatment effect was detected (P = 0.03) for dry matter intake, being greater in NAR vs. CON, LAS, and VRM bulls, and similar (P > 0.48) between CON, LAS, and VRM bulls. A tendency was detected (P = 0.09) for feed efficiency, which was greater (P < 0.02) in NAR bulls vs. CON and VRM, and similar (P = 0.36) between NAR and LAS bulls. From day 112 to 140, bulls receiving NAR were heavier (P < 0.03) vs. CON, LAS, and VRM bulls, but no differences were observed (P > 0.51) between CON, LAS, and VRM bulls. Collectively, ruminal fermentation profile and intake were impacted by NAR supplementation, which partially contributed to the enhanced performance of Nellore bulls receiving a forage-based diet.. Feed additives are nutritional tools that benefit dietary digestibility and nutrient utilization, alter ruminal fermentation routes, and improve cattle growth and efficiency, thus increasing productivity and profitability in beef cattle systems. Nonetheless, most of the current research focuses on supplementing feed additives in high-concentrate diets. Leaving a significant gap in understanding the influence of feed additives in cattle consuming forage-based diets, especially molecules capable of altering the fermentation process and, consequently, beef cattle performance. Therefore, this experiment aimed to evaluate the impacts of supplementing narasin (NAR), lasalocid (LAS), or virginiamycin (VRM) on rumen fermentation parameters, apparent nutrient digestibility, feed intake, and performance of Bos indicus Nellore cattle consuming a forage-based diet. Including commercially available feed additives into forage-based diets did not impact nutrient intake and digestibility of nutrients. The inclusion of NAR affected ruminal fermentation parameters toward propionate production, positively contributing to animal performance. Ruminal fermentation characteristics and animal growth were not impacted by dietary LAS and VRM, which could be attributed to the dose used in the current experiment, despite the manufacturer’s recommendation. This research provides insights into NAR as an important feed additive for forage-based beef cattle diets.

Topics: Animal Feed; Animals; Body Weight; Cattle; Diet; Dietary Supplements; Digestion; Fermentation; Lasalocid; Male; Propionates; Rumen

Topics: Animals; Chickens; Chromatography, Liquid; Coccidiosis; Eggs; Food Analysis; Humans; Lactones; Lasalocid; Liquid-Liquid Extraction; Monensin; Nigericin; Piperidines; Poultry; Pyrans; Quinazolinones; Robenidine; Tandem Mass Spectrometry; United States; United States Food and Drug Administration

Ionophore antimicrobials are heavily used in the livestock industries, both for preventing animal infection by coccidia protozoa and for increasing feed efficiency. Ionophores are excreted mostly unmetabolized and are released into the environment when manure is land-applied to fertilize croplands. Here, an analytical method was optimized to study the occurrences of five ionophore residues (monensin, lasalocid, maduramycin, salinomycin, and narasin) in dairy manure after solid-liquid separation and further treatment of the liquid manure by a membrane-based treatment system. Ionophore residues from the separated solid manure (dewatered manure) and suspended solids of manure slurry samples were extracted using ultrasonication with methanol, followed by sample clean-up using solid phase extraction (SPE) and subsequent analysis via liquid chromatography-tandem mass spectrometry (LC-MS/MS). The use of an ethyl acetate and methanol (1:1 v:v) mixture as an SPE eluent resulted in higher recoveries and lower method quantitation limits (MQL), when compared to using methanol. Overall recoveries from separated solid manure ranged from 73 to 134%. Liquid manure fractions were diluted with Nanopure™ water and cleaned up using SPE, where recoveries ranged from 51 to 100%. The developed extraction and LC-MS/MS methods were applied to analyze dairy manure samples subjected to an advanced manure treatment process involving a membrane-based filtration step (reverse osmosis). Monensin and lasalocid were detected at higher concentrations in the suspended solid fractions (4.40-420 ng/g for lasalocid and 85-1950 ng/g for monensin) compared to the liquid fractions (

Topics: Animals; Anti-Infective Agents; Cattle; Chromatography, Liquid; Coccidia; Coccidiosis; Ionophores; Lactones; Lasalocid; Manure; Methanol; Monensin; Pyrans; Solid Phase Extraction; Tandem Mass Spectrometry

Topics: Animals; Anti-Bacterial Agents; Biofilms; Cattle; Female; Gram-Positive Bacteria; Ionophores; Lasalocid; Mastitis, Bovine; Microbial Sensitivity Tests; Monensin; Pyrans; Staphylococcal Infections; Staphylococcus; Streptococcal Infections; Streptococcus

Hydrolytic and photolytic degradation were investigated for the ionophore antibiotics lasalocid, monensin, salinomycin, and narasin. The hydrolysis study was carried out by dissolving the ionophores in solutions of pH 4, 7, and 9, followed by incubation at three temperatures of 6, 22, and 28 °C for maximum 34 days. Using LC-MS/MS for chemical analysis, lasalocid was not found to hydrolyse in any of the tested environments. Monensin, salinomycin, and narasin were all stable in neutral or alkaline solution but hydrolysed in the solution with a pH of 4. Half-lives at 25 °C were calculated to be 13, 0.6, and 0.7 days for monensin, salinomycin, and narasin, respectively. Absorbance spectra from each compound indicated that only lasalocid is degraded by photolysis (half-life below 1 h) due to an absorbance maximum around 303 nm, and monensin, salinomycin, and narasin are resistant to direct photolysis because they absorb light of environmentally irrelevant wavelengths.

Topics: Anti-Bacterial Agents; Half-Life; Hydrogen-Ion Concentration; Ionophores; Lasalocid; Models, Chemical; Monensin; Photolysis; Pyrans; Temperature; Water Pollutants, Chemical

A published confirmatory method for the quantitative determination of four ionophoric coccidiostats (lasalocid, monensin, salinomycin and narasin) in eggs and broiler meat has been further developed. It is proposed for replacement of liquid chromatography methods previously used in analysis of ionophoric coccidiostats. The samples were extracted with acetonitrile and purified on a silica solid phase extraction column. Purified samples were analysed by liquid chromatography-mass spectrometry and the method, was validated according to the Commission Decision 2002/657/EC. The validation parameters selectivity, linearity, specificity, precision, recovery, decision limit (CCalpha) and detection capability (CCbeta) were determined. The recoveries of coccidiostats analysed ranged from 64-99% in eggs and 62-100% in broiler meat. CCalpha varied from 0.8-1.4 microg/kg in eggs and from 1.5-2.5 microg/kg in broiler meat. CCbeta varied from 0.9 microg/kg to 2.0 microg/kg in eggs and from 1.7-3.2 microg/kg in broiler meat.

Topics: Animals; Chickens; Chromatography, Liquid; Coccidiostats; Eggs; Food Contamination; Lasalocid; Mass Spectrometry; Meat; Monensin; Pyrans; Reproducibility of Results

A sensitive and selective liquid chromatographic tandem mass spectrometric method (LC/MS/MS) for the simultaneous detection of the ionophoric coccidiostats narasin, monensin, lasalocid and salinomycin in whole eggs has been developed. A very simple sample preparation consisting of an extraction with an organic solvent was carried out. Sample extracts were injected into the LC/MS/MS system on a C18 column and an isocratic elution was performed. Nigericin was used as internal standard. The precursor ions produced by electrospray positive ionisation were selected for collisional dissociation with argon into product ions. Validation of the methods was performed based on Commission Decision 2002/657/EC.1 CC(alpha) was found to be 1 microg/kg for all four compounds. Monitoring of Belgian egg samples in 2004 revealed that residues of salinomycin, lasalocid and monensin could be found.

Topics: Animals; Chromatography, High Pressure Liquid; Coccidiostats; Eggs; Food Contamination; Ionophores; Lasalocid; Monensin; Pyrans; Spectrometry, Mass, Electrospray Ionization

A rapid and very effective analytical procedure for the simultaneous determination of four polyether antibiotics (PEs) lasalocid, monensin, salinomycin and narasin in poultry feeds was tested. PEs were extracted from samples using methanol and without and clean-up derivatized with 2,4-dinitrophenylhydrazine (DNP) in an acidic medium at 55 degrees C. The derivatization mixture was analyzed directly on an ODS column (150 x 4.6 mm, 5 microns) with methanol--1.5% aqueous acetic acid (90:10, v/v) as eluent and UV detection was carried out at 305/392 nm. The recoveries of the PEs from spiked samples were 85-100% with RSDs of 4-10% in a concentration range of 50-150 mg/kg.

Topics: Animal Feed; Animals; Chromatography, Liquid; Coccidiostats; Indicators and Reagents; Lasalocid; Monensin; Phenylhydrazines; Poultry; Pyrans; Reference Standards; Reproducibility of Results; Spectrophotometry, Ultraviolet; Veterinary Drugs

Monensin, salinomycin and narasin were detectable in six, two and one, respectively, out of 161 eggs surveyed in Northern Ireland in 1994. In all cases, the concentrations detected were less than 2.5 ng/g. Lasalocid was detectable in 107 eggs at concentrations ranging from 0.3 to 129 ng/g. Cross-contamination of unmedicated feeds with monensin during feed manufacture (up to eight batches of unmedicated feed contaminated with monensin) was similar to that previously observed for lasalocid (up to nine batches contaminated). Therefore differences in the incidence in eggs could not be explained by differential carry-over during feed manufacture. In a feeding trial it was shown that the relative ability of monensin, salinomycin and lasalocid to accumulate in eggs was in the ratio 0.12:3.3:63 ng/g egg per mg/kg feed, respectively. This indicated that the potential for monensin and salinomycin to cause residues in eggs was very low, by comparison with lasalocid. In 1995, a granular formulation of the lasalocid premix was introduced into the United Kingdom that decreased the carry-over of this drug from medicated to unmedicated feed. Six months after the introduction of this formulation, the incidence of lasalocid residues in eggs (21%) was lower than that found (66.5%) in an earlier survey (1994) carried out, and published, by this laboratory.

Topics: Animal Feed; Animals; Chickens; Coccidiostats; Drug Residues; Eggs; Food Contamination; Humans; Incidence; Ionophores; Lasalocid; Monensin; Northern Ireland; Pyrans

Streptococcosis is a major disease of several fish species in Australia, Japan and South Africa. The minimum inhibitory concentration of some ionophores (lasalocid, monensin, narasin and salinomycin) was determined in vitro for an Enterococcus-like species pathogenic for rainbow trout (Oncorhynchus mykiss) in Australia. Forty isolates of the fish pathogen were tested, together with control strains of Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212 and Streptococcus bovis ATCC 9809. The minimum inhibitory concentrations (MIC) of erythromycin, the drug of choice for controlling streptococcosis, ranged between 0.1 and 0.8 microgram/ml whereas the MIC values for the ionophores ranged between 0.2 and 1.5 micrograms/ml. Of the ionophores tested, narasin was the most inhibitory (0.2-0.4 microgram/ml), while monensin was the least inhibitory (0.4-1.5 micrograms/ml). Salinomycin was marginally more inhibitory (0.4-0.8 microgram/ml) than lasalocid (0.8 microgram/ml).

Topics: Animals; Anti-Bacterial Agents; Enterococcus; Erythromycin; Fish Diseases; Gram-Positive Bacterial Infections; Ionophores; Lasalocid; Microbial Sensitivity Tests; Monensin; Oncorhynchus mykiss; Pyrans

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

Topics: Animal Feed; Anti-Bacterial Agents; Chromatography, Thin Layer; Furans; Lasalocid; Monensin; Pyrans

Free Eimeria tenella sporozoites were exposed to the anticoccidial ionophores monensin, lasalocid, narasin, or salinomycin for 4 hr at 40 C, whereupon the drugs were removed by dilution centrifugation and the parasites inoculated into cultures of chick kidney cells. Cultures were fixed and stained at 4 and 96 hr postinoculation to determine the effect of ionophore uptake by the extracellular sporozoites on invasion and development. Pretreatment with each of these antibiotics significantly reduced the number of intracellular sporozoites and dramatically inhibited asexual development. These effects were dose-dependent. Exposure of free (extracellular) sporozoites to monensin at 40 C caused a significant decline in the number of surviving organisms over time as compared to nontreated sporozoites. This response also appeared to be dose-dependent. Scanning and transmission electron microscopy revealed that the surface of the treated sporozoites was very irregular and the organisms often exhibited a gross swelling. These results indicated that free Eimeria tenella sporozoites may incorporate a potentially lethal concentration of the polyether ionophorous antibiotics and that a coccidiocidal activity may be expressed whether or not penetration of host's cells occurs.

Topics: Animals; Cells, Cultured; Chickens; Dose-Response Relationship, Drug; Eimeria; Furans; Ionophores; Kidney; Lasalocid; Monensin; Pyrans

Topics: Adenosine Triphosphatases; Adenosine Triphosphate; Animals; Anti-Bacterial Agents; Cations, Monovalent; Dinitrophenols; In Vitro Techniques; Ionophores; Lasalocid; Male; Mitochondria, Liver; Mitochondrial Swelling; Monensin; Pyrans; Rats; Valinomycin

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