EFFECT OF SUPPLEMENTING THE HENS DIET WITH VITAMIN-A ON THE ACCUMULATION OF VITAMIN-A AND VITAMIN-E, ASCORBIC-ACID AND CAROTENOIDS IN THE EGG-YOLK AND IN THE EMBRYONIC LIVER

1. The effect of a range of supplementations of vitamin A to the layin g hen on the concentration of vitamins A, E, ascorbic acid and caroten oids in the maternal liver, the egg yolk and the embryonic liver were investigated. 2. Four groups of 25 Rhode Island Red hens were fed on s tandard layer-breeder diets with concentrations of supplemented vitami n A ranging from 0 to 120 mu g/g retinol equivalents from 28 weeks of age. After 3 months, the concentration of vitamin A in the maternal li ver was found to be greatly enhanced in proportion to the increasing r ates of supplementation with the vitamin. However, the concentration o f vitamin E in the maternal liver was markedly reduced by high dietary contents of vitamin A. 3. The concentration of vitamin A in the yolk of the hens' eggs was markedly increased by the dietary supplementatio n. However, the concentration of both vitamin E and carotenoids in the yolks were significantly reduced by high dietary contents of vitamin A. 4. The concentration of vitamin A in the liver of the embryo and th e day old chick was greatly increased by the high concentrations of ma ternal vitamin A provision. However, the concentration of vitamin E, c arotenoids and ascorbic acid in the embryonic/neonatal liver were sign ificantly reduced by high contents of vitamin A in the maternal diet. 5. The susceptibility of the embryonic/neonatal liver to lipid peroxid ation was significantly increased as a result of high provisions of ma ternal vitamin A. 6. It is concluded that excessive provision of vitam in A to the laying hen results in an adverse effect on vitamin E, caro tenoids and ascorbic acid in the embryonic/neonatal liver and can comp romise the antioxidant status of the progeny.