An apparent phosphate selenium interaction in weaner sheep.

The severity of selenium dependent nutritional myopathy in weaner sheep was markedly increased by the ruminal infusion of soluble phosphate (6.0 g d-1). Liver selenium concentration was also significantly lower in the sheep infused with sodium phosphate than in sheep fed the same diet and infused with sodium chloride. There were no significant differences in the selenium concentrations of other tissues examined (kidney, heart, skeletal muscle, blood). Blood glutathione peroxidase (GSH.Px) activity in the sheep affected with nutritional myopathy was considerably higher than values generally accepted to indicate a selenium deficiency. The results indicated that there was an interaction in the animal between selenium and phosphate leading to lower liver selenium concentrations. Results obtained from sheep intraruminally dosed with 75[Se]selenate suggested that an interaction between selenium and phosphate could also occur in the gastrointestinal tract.