Effect of Added Dietary Selenium on Metabolism and Tissue Distribution of Radioactive and Stable Selenium in Calves

Abstract

Stable selenium content and 75Se retention of an oral 75Se dose were determined in tissues of calves fed either 0, .1, or 1.0 ppm supplemental selenium with a practical diet containing .3 ppm natural selenium. Kidney and small intestinal retentions of 75Se were very sensitive to dietary level and were reduced about 35% and 65% with .1 and 1.0 ppm added selenium. In most other tissues, 75Se was reduced (P>.05) with 1.0 ppm added dietary selenium. Stable selenium contents were not elevated in any tissue sampled with .1 ppm supplemental selenium. Feeding 1.0 ppm added selenium to calves for 28 days, however, elevated selenium levels in the liver 192%, heart 88%, and blood 64%; but increases in the kidney, muscle, and pancreas were not significant. Specific activities of 75Se were lowered significantly in the kidney, blood, liver, and heart with 1.0 ppm added selenium, indicating reduced selenium retention and/or increased tissue turnover rate. Calf weight gains were not affected by dietary selenium supplementation.