The Selenium Needs of Laying and Breeding Hens

Experiments were conducted to determine the quantitative relationship between supplemental dietary selenite and the deposition of selenium in eggs of Single Comb White Leghorn pullets consuming diets adequate with respect to all other nutrients, including vitamin E and a synthetic antioxidant, and to evaluate the influence of vitamin E, increased antioxidant levels, and an unsaturated fat on the efficacy of supplemental selenite for performance of laying and breeding hens. Results indicate that dietary levels of ca .05 ppm selenium are adequate to sustain egg production in laying pullets but that levels less then .10 ppm result in a deficiency of selenium dependent glutathione peroxidase. A level of ca .10 ppm selenium in vitamin E-deficient diets is required for optimal hatchability and subsequent performance of progeny. When diets of laying hens formulated with selenium-deficient ingredients were supplemented with .10 ppm selenium as Na2 SeO3, the selenium concentration of the edible contents of eggs was found to be .26 ppm after 20 weeks of feeding. This concentration is within a nutritionally important range and is far below levels shown to have any toxic effects on experimental animals.