A Chick-Growth Factor in Egg Yolk

Publisher Website
Google Scholar
Abstract
Fresh or dried yolk was shown to contain an unidentified chick growth factor (s) not identical with the fish solubles factor. Preliminary fractionation procedures have shown that the active principle is fat soluble since it can be extracted from dried yolk by the common fat solvents. The yolk factor is not identical with oleic acid, linoleic acid, or lecithin. The non-phospholipid and the non-saponifiable portions of yolk extracts contain the growth factor. The yolk factor is destroyed by hot but not by cold saponification. Adjustments in the calorie: protein ratio of the diet and omission of alfalfa leaf meal (source of saponins) from the ration did not affect the growth response to yolk.