The purpose of this study was to investigate whether the beneficial effects which the consumption of fish oil imparts on hemostatic function can be modified by the level of dietary selenium. Male Sprague Dawley rats were fed for eight weeks semipurified diets containing 7% corn oil (by weight) or 5.5% fish oil (MaxEPA) plus 1.5% corn oil with or without selenium supplementation. The indicators of selenium status (glutathione peroxidase activity and selenium level) were significantly lower in the rats given inadequate selenium, regardless of the type of fat fed. In the animals fed adequate selenium, these same indicators tended to be lower when fish oil was fed. Although feeding of fish oil increased hepatic and aortic malondialdehyde (MDA), selenium supplementation decreased its level in the liver. Selenium deficiency led to a decrease in the relative weight percent of 22:6 n-3 in aorta and plasma. Increases in the levels of 20:5 n-3, 22:5 n-3, 22:6 n-3, 20:3 n-6 and a decrease in the level of 20:4 n-6 were observed in plasma total lipids and aortic and hepatic phospholipids when fish oil was fed. The increased level of 20:3 n-6 suggests that delta 5-desaturase activity was decreased by fish oil feeding. The level of aortic 6-keto-prostaglandin F₁alpha (6- keto-PGF₁alpha) was highest in the rats fed diets that contained corn oil but no selenium supplementation; selenium supplementation, however, eliminated the difference in the level of 6-keto-PGF₁alpha between fish oil and corn oil fed groups. The levels of thromboxane B₂ (TXB₂) and ADP-induced platelet aggregation were decreased significantly by fish oil feeding and tended to be lower with selenium supplementation. Selenium supplementation did not increase bleeding time while fish oil feeding did. These data indicate that selenium supplementation may decrease fish oil induced lipid peroxidation in liver: this is reflected in the lower hepatic MDA levels in the fish oil fed animals with selenium supplementation and the increased 22:6 n-3 levels in aorta and plasma. Selenium deficiency led to an increase in the level of 6-keto-PGF₁alpha in the rats fed corn oil. Its effects on TXB₂ level and ADP-induced platelet aggregation are marginal. Overall the beneficial effect of selenium supplementation on hemostatic function appears weaker than that of fish oil feeding. / Graduation date: 1990

Graduation date: 1993