Effect of Dietary Antibiotic upon Feed Efficiency and Protein Requirement of Growing Chickens

Abstract

SINCE the report of Stokstad et al. (1949) that a product resulting from the growth of Streptomyces aureofaciens contains an unidentified factor for the growth of chicks, many workers including Berg et al. (1950), Biely et al. (1951), Reed and Couch (1950), and Sherwood and Couch (1950) have reported similar findings with this or comparable products. Studies by Stokstad and Jukes (1950), Groschke and Evans (1950), and McGinnis et al. (1950) have indicated that the growth promoting constituents of these products are aureomycin and vitamin B12. Whitehill et al. (1950) have also demonstrated the stimulatory effect of aureomycin on the growth of chicks. In contrast to these results, Scott and Glista (1950) reported that aureomycin did not increase chick growth except for a slight response during the first few weeks with ad libitum feeding and that it had no effect when feed intake was equated. Reports on the effect of . . .