Protein Requirement of Broilers as Influenced by Antibiotics

McGINNIS (1951) reported that growth to four weeks of poults fed a diet containing 24 percent protein and penicillin was comparable to that obtained with protein levels as high as 28 percent when no antibiotic was added. Penicillin stimulated growth at all levels of protein tested. Machlin et al. (1952) concluded from their results that the protein requirement of young chickens appeared to be decreased slightly by the addition of aureomycin to the diet. These birds were reared in batteries to six weeks of age and were fed all-vegetable diets. Slinger et al. (1952) found that penicillin or aureomycin did not alter the protein requirement of broilers to ten weeks of age. The penicillin studies were conducted using Barred Plymouth Rock males reared on litter and fed practical-type rations; the aureomycin study was conducted using crossbred male chicks reared in batteries and fed diets containing some animal protein ingredients. Scott …