title: Effects of diet and bacitracin on growth, feed efficiency, and populations of Clostridium perfringens in the intestine of broiler chicks.
abstract: Experiments were conducted to demonstrate the activity of bacitracin as a growth permittant for poultry and to further elucidate the mode of action of antimicrobial agents for that purpose. Supplementing a soybean protein and sucrose-based diet with 2.2, 11, and 55 ppm of bacitracin resulted in significant improvements in weight gain and feed efficiency of chicks fed the higher levels. In a second experiment, graded levels of bacitracin from 1.1 to 55 ppm were fed. A regression analysis of the index scores, the combined effects of both weight gain and feed efficiency, on the log of the significant dose levels of 5.5 to 27.5 ppm gave a linear response line with r = .996. Based on the equation, the ineffective level of the antibiotic was determined to be 4 ppm and the maximum effective level 31 ppm. Supplementing the soybean protein and sucrose-based diet with levels of 5.5, 16.5, and 55 ppm of bacitracin reduced the numbers of Clostridium perfringens organisms in ileal contents of chicks (all P less than .05). Chicks fed a level of 1.1 ppm, a level that did not give a growth response, had numbers of the organism present that were not significantly different from controls. Supplementing a soybean meal and corn-based diet with a level of 55 ppm of bacitracin did not significantly affect weight gain, feed efficiency, or numbers of C. perfringens in the ileum of chicks.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D001414:Bacitracin / Q000494:pharmacology*; D001835:Body Weight / Q000187:drug effects; D002645:Chickens / Q000382:microbiology / Q000502:physiology*; D003016:Clostridium perfringens / Q000187:drug effects*; D004032:Diet; D004734:Energy Metabolism / Q000187:drug effects; D005503:Food Additives; D007082:Ileum / Q000382:microbiology; D007422:Intestines / Q000382:microbiology*; D008297:Male
chemical_list: D005503:Food Additives; D001414:Bacitracin