Influence of Diet Composition on Chick Growth Response to Different Antibiotics, Feed Additives and Combination of the Additives

Abstract Three experiments were conducted to determine the effect of different diet formulations on the growth response of chicks to different antibiotics and antimicrobials as single diet supplements or in combinations. The first experiment involved the use of a corn-soybean type diet and a diet containing a high level of dry beans (Phaseolus vulgaris). Both diets were supplemented with two levels of MD bacitracin and procaine penicillin, and each of the antibiotic levels was also fed in combination with a low level of 3-nitro phenylarsonic acid. In the second experiment, starter and finisher broiler diets containing a high level of dry beans were singly supplemented with two levels of MD bacitracin or the two levels in combination with a low level of 3-nitro phenylarsonic acid. In the third experiment, growth obtained with diets containing a high level of rye or beans and supplemented with procaine penicillin and nitrovin (Payzone) was compared with that obtained with a corn based diet. The results obtained indicate significant effects of diet on chick growth. Diets containing corn gave better growth than those containing rye or beans. Growth response to antibiotic supplements was greater with the diets containing rye or beans, as compared with those based on corn. A high level of MD bacitracin supplement (50 p.p.m.) was significantly more effective than lower dosage levels (4 to 10 p.p.m.), regardless of diet type. Evidence for an additive effect of MD bacitracin and 3-nitro phenylarsonic acid was stronger when bacitracin was used at the higher dosage level. Procaine penicillin and nitrovin were equally effective in promoting chick growth, regardless of diet type.