A differential response in turkey poults to various antibiotics in diets designed to be deficient or adequate in...

Two experiments, each consisting of two trials, were conducted with day-old Nicholas Large White turkey poults to compare the effectiveness of four antibiotics for growth promotion and the utilization of sulfur amino acids. A corn-soybean meal basal diet that contained no supplemental methionine, choline, or inorganic sulfate was used in order to furnish nutritional stress. The diet was calculated to contain 25.4% protein, .448% methionine, .403% cystine, 1014 mg/kg choline, and 2990 kcal metabolizable energy/kg. In Experiment 1, a 2 X 4 factorial arrangement of treatments was used. This included two levels, (0% (control) and .18%), of supplemental DL-methionine and no antibiotic or bacitracin MD, flavomycin, or virginiamycin; antibiotics were fed at 50, 2, and 20 g/ton, respectively. In Experiment 2, lincomycin also was included as a treatment (at 4 g per ton) resulting in a 2 X 5 factorial arrangement of treatments. Only the addition of Virginiamycin to the control diet in Experiment 1 resulted in significantly increased body weights. Supplementation by .18% methionine increased body weights and feed efficiency. In addition, all three antibiotics increased body weights significantly when added to the .18% methionine diets. Feed efficiency values were improved by all four antibiotics at both methionine levels. In Experiment 2, increases in body weights similar to those in Experiment 1 were obtained with the addition of .18% methionine to the basal diets. Addition of lincomycin and virginiamycin improved body weights and feed efficiencies in the presence and absence of supplemental methionine.