Growth, Reproduction, and Tissue Concentrations of Selenium in the Selenium-depleted Rat

Abstract

Selenium-depleted rats were obtained by feeding a purified low selenium amino acid diet to commercially available weanling rats or by breeding females maintained on a Torula yeast diet. Both diets were fortified with dl-a- tocopherol. Selenium concentrations in blood, liver and skeletal muscle of wean ling rats obtained commercially and fed the purified diet decreased from initial values of 0.32, 0.60, and 0.23 ppm to 0.05, 0.04, and 0.02 ppm, respectively, in 20 weeks. Seventy percent of these declines occurred in the first 6 weeks. Supple mentation of the purified diet with 0.5 ppm selenium in selenomethionine im proved growth and produced increases in blood and liver selenium for 20 weeks but skeletal muscle selenium remained constant. Second and third litters of females fed the Torula diet were hairless at weaning and had blood concentra tions below 0.07 ppm. Second and third litter offspring of these depleted dams showed improved body and hair growth when fed the diet of their dams supple mented with 0.50 ppm selenium as selenomethionine. The females maintained for 6 months on the Torula yeast reproduced normally through three Utters. Their blood selenium values decreased from 0.52 to 0.06 ppm during this time. Affirma tive evidence is presented that selenium is a required nutrient, and regimens for producing selenium-depleted animals are discussed. J. Nutr. 101: 761-766, 1971.