Effects of Certain Antibiotics on Protein Utilization by Broilers

RESULTS indicative of a possible “sparing” effect of low levels of certain antibiotics on the protein requirement of broilers were reported by Machlin et al. (1952), Weakley et al. (1953), and West and Hill (1955). The work of Scott et al. (1952), Slinger et al. (1952), Biely et al. (1952) and Matterson et al. (1952) indicated that no sparing effect of antibiotics on protein occurred in chicks. White-Stevens and Zeibel (1954) found that low levels of aureomycin produced the greatest effect on growth at a protein level of 16 percent, but that high levels of aureomycin gave the greatest effect on growth at a protein level of 22 percent. Energy levels were held relatively constant for the different protein levels, varying from 900 to 950 Calories of productive energy per pound of feed. The work of Combs and Romoser (1955) showed that the protein needs of the young chicken varies . . .