Studies on Carotenoid Metabolism

Abstract

The lowering of the carotenoid pigments in the blood and livers of chickens following the administration of a high vitamin A diet is greater than that in the blood or milk of cows on a similar dietary regime. This is not caused by the failure to absorb similar amounts of the carotenoids, but must be attributed to the more rapid destruction. The main pigments in the chickens are carotenols. Failure of the chicken to store carotene is not due to lack of absorption of this substance, but must be attributed to its transformation to other non-chromogenic compounds. There is evidence of a toxic action of large doses of vitamin A, in the form of shark liver oil, to the 2-week-old chickens. This toxic action was only noted in the smallest birds.