Effect of Dietary Vitamin A on Egg Yolk Retinol and Tocopherol Levels

Abstract

Vitamin A deficiency is a serious public health problem in developing countries, and it causes death or blindness among children in these countries. Fortification of food, such as eggs, could be an important source of vitamins to control deficiency. To evaluate the effect of dietary levels of vitamin A upon reproductive performance, egg quality, and egg yolk retinol and tocopherol concentrations, laying hens were fed a basal diet (commercial ration) supplemented with increased retinyl acetate. It was observed that hen performance was not significantly affected by addition of vitamin A. Progressive increase in the incorporation of retinol into egg yolk was verified when vitamin A was supplemented to the basal diet; the percentage of increment reached 50.6% with 25,000 IU of dietary retinyl acetate/kg. Egg yolk retinol content increased linearly as dietary vitamin A increased. However, significant decreases in the egg yolk tocopherol concentrations showed an adverse effect of vitamin A supplementation. The nutritional value of eggs, related to vitamin A, can be improved by dietary manipulation of hen diets.