Measurement and Differentiation of Unidentified Chick Growth Factors Using a New Semi-Purified Ration

THE presence of unidentified nutritional factors in various ingredients fed to chicks has been well established. Much of the literature on this subject has been reviewed by Menge et al. (1952). Considerable evidence has accumulated pointing to a multiplicity of unidentified factors required by the chick. Carlson et al. (1949) postulated the presence of two distinct factors, one in fish meal and the other in dried brewers yeast. Stokstad and Jukes (1950) reported that at least part of the chick response to Streptomyces aureofaciens materials was due to chlortetracycline. Kohler and Graham (1951) concluded that the unidentified forage crops juice factor is different from vitamin B13, whey factor, or antibiotic effect. Couch et al. (1952) found one unidentified chick factor in distillers dried solubles, dried whey, and whey product and another in fish meal. Edwards et al. (1953) reported that fish solubles and penicillin mycelium residue contain the same unidentified …