Effect of doses of protected polyunsaturated fatty acids on indicators of selenium status of sheep.

In monogastric animals, dietary polyunsaturated fatty acids (PUFA) have been shown to increase glutathione peroxidase (GSH-Px) activity in plasma and erythrocytes and to decrease plasma selenium concentration. Ruminants feeding on grass can have a high intake of PUFA. In this experiment, sheep were dosed orally with protected PUFA (Pr-PUFA) for five weeks at 5 g kg liveweight-1 three times per week for the first week and at 8 g kg-1 for the following four weeks. The Pr-PUFA did not affect GSHPx activity in erythrocytes or plasma or liver selenium concentration, but did reduce the selenium concentration in muscles by between 20 and 30 per cent. In addition, liver iron concentration was reduced by about 42 per cent. The results suggest that dietary PUFA may affect the distribution of selenium rather than its absorption.