Deficiency of Unidentified Vitamins in Practical Chick Rations

Several groups of research workers have reported the existence of unidentified members of the vitamin-B complex required by the chick for the prevention of nutritional deficiency. Among these are factor U of Stokstad and Manning (1938), factor R and factor S of Schumacher, Norris and Heuser (1940), vitamin Bc of Hogan and Parrott (1940), and vitamin B10 and vitamin B11 of Briggs, Luckey, Elvehjem and Hart (1943). Factor U, factors R and S and vitamin B11 were reported to be required for chick growth, vitamin Bc, for the prevention of anemia and vitamin B10 for feather development. These discoveries were made by making use of specially devised experimental diets. As a consequence no evidence was obtained of the need for any of these vitamins in practical chick feeding. Recently, however, results have been obtained at this laboratory which show that certain chick rations containing limited amounts of protein of animal . . .