According to studies conducted with 236 bobwhite quail chicks at Patuxent Research Refuge, crystalline carotene in cottonseed oil fed at levels of 3000 I.U. (the requirement for optimum growth), 5000 I.U., and 25,000 I.U. per pound of feed, was utilized only 1/3 to 1/7 as efficiently as vitamin A alcohol; 1/2; to 1/10 as natural vitamin A ester; and 1/4 to 1/17 as vitamin A acetate, based on the storage of vitamin A in the liver. The carotene in the natural carrier, alfalfa leaf meal, was assimilated as effectively as was crystalline carotene in cottonseed oil, when both were fed at 5000 I.U. per pound of feed. Crystalline carotene when fed at a level over 8 times the requirement of the quail for maximum growth, or 25,000 I.U. per pound of feed, was stored as vitamin A in the livers of pen-reared quail to an extent comparable to the levels found in certain young wild quail. Vitamin A acetate was utilized more efficiently by quail than either vitamin A alcohol or the natural vitamin A ester. There was considerable individual variation in storage of vitamin A by quail on the same diet, and with the same or similar parental background.
