Effect of High Dietary Vitamin A Levels on the Utilization of Carotenoids by Broilers

Abstract

HIGH dietary levels of vitamin A have been reported to reduce the carotenoid content of egg yolks, liver and blood of hens (Deuel et al., 1943), skin carotenoids of chicks (Hammond and Harshaw, 1941), and the carotenoid content of the plasma and liver of chicks (Mattson and Deuel, 1943). Rubin and Bird (1946) showed that inhibition of pigmentation takes place even when there is sufficient storage of vitamin A in the body. The source of vitamin A employed in most of the early work was either shark liver oil or cod liver oil, and, therefore, it was rather difficult to conclude whether the interference in the carotenoid utilization was due to vitamin A per se or some impurity in the oils. Recently, Donovan et al. (1961) and Sunde (1962) observed that high dietary levels of vitamin A palmitate depressed egg yolk color.Since high dietary vitamin A levels are sometimes…