Unidentified Growth Factors Required by Chicks and Poults: 2. Fractionation of a Factor in Liver

Abstract

SEVERAL investigators have presented evidence which reveals that unidentified factors are required for growth of chicks and poults. Much of the work conducted with chicks has been reviewed by Combs (1951) and Menge et al. (1952). The latter workers also presented results which indicate that two distinct unidentified growth factors are required by chicks. One of these was present in certain liver preparations and dried brewers’ yeast, while the other was present in dried whey products. Studies with poults also reveal the presence of unidentified growth factors in fish meal (Combs and Shaffner, 1950; McGinnis et al., 1952; and Sizemore and Combs, unpublished), fish solubles (Patrick, 1951; and Atkinson and Couch, 1951), crab meal (Combs and Shaffner, 1950), dried brewers’ yeast (Combs and Shaffner, 1950; Scott, 1951; and Sizemore and Combs, unpublished), grass and alfalfa juice, distillers’ dried solubles, and skim milk (Scott, 1951), dried whey, butyl molasses solubles, butyl .