Unidentified Growth Factors for the Chick in Vegetable Oils and Fatty Acid Concentrates

RESEARCH concerning the fat and fatty acid requirements of chicks has been limited and controversial. The early work using diets which had been solvent extracted to remove fat demonstrated that the chick’s requirement for fat was negligible or nonexistent. Later work with crystalline vitamins and semi-purified diets has indicated that the chick requires fat or substances contained in fat for normal growth and livability. Russell, Taylor and Polskin (1940) stated that extracting an all-mash starter with diethyl ether until the diet contained 0.1 percent or less of ether extractables did not retard chick growth significantly up to 14 weeks of age. Davis and Upp (1941) reported that extraction of an all-mash ration for 30 hours with isopropyl ether decreased the growth of chicks but that this slight difference disappeared by the time the pullets reached maturity. Reiser (1950a) demonstrated that a fat-free semipurified ration produced poor livability and growth and …