Unidentified Factors in Poultry Nutrition

THE isolation and availability of crystalline vitamin B12 has stimulated the investigation of unidentified growth factors for poultry. This work has been comprehensively reviewed by Combs (1951), Menge et al. (1952a), and Briggs (1952). Studies conducted in this laboratory have shown condensed fish solubles to contain an unidentified chick growth factor, or factors, Lillie et al. (1953). The present investigation was undertaken to prepare a potent concentrate of this factor and to study some of its properties. EXPERIMENTAL PROCEDURE The method of assay used in the following studies has been described by Lillie et al. (1953). The stability of the growth factor to autoclaving at various pH values was determined by adding either concentrated sodium hydroxide or concentrated hydrochloric acid to a sample of fish solubles diluted with an equal quantity of water. The total volume, after adjustment of pH, was kept uniform for each sample. Each lot was autoclaved …