Antioxidant Effects on Selenium and Vitamin E Function in the Chick

Abstract

Experiments were conducted to determine the effects of high-level antioxidant feeding on selenium and vitamin E function in vitamin E-depleted chicks fed a semipurified basal diet low in selenium and tocopherols. Three different antioxidants were fed: ethoxyquin (6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline), ascorbic acid and vitamin A. Each antioxidant significantly reduced selenium requirements for growth and prevention of exudative diathesis and mortality in vitamin E-deficient chicks. Also, plasma activities of glutathione peroxidase of chicks receiving marginal selenium levels were significantly increased. Ethoxyquin and ascorbic acid treatments reduced the dietary vitamin E requirement for prevention of in vitro ascorbic acid-stimulated peroxidation in hepatic microsomes in selenium-adequate chicks. However, vitamin A treatment severely depressed the plasma concentration of tocopherols and increased microsomal peroxidation without response to dietary vitamin E. The results indicated that antioxidants increased the utilization of dietary selenium without severely affecting vitamin E antioxidant function, except for vitamin A which appeared to antagonize vitamin E absorption directly.