Differential effects of dietary eicosapentaenoic and docosahexaenoic fatty acids on lowering of triglyceride and cholesterol levels in the serum of rats on hypercholesterolemic diet.

This investigation was attempted in order to further clarify the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on lipid metabolism in rats. Ninety-three percent ethyleicosapentaenoate (EPAconc) and 91% ethyl-docosahexaenoate (DHAconc) were used and supplied at the 3% level to a hypercholesterolemic basal diet which contained 5% lard. Four experimental diets were prepared from (1) 5% olive oil, (2) 2% olive oil +3% ethyl-linoleate, (3) 2% olive oil +3% EPAconc, and (4) 2% olive oil +3% DHAconc plus hypercholesterolemic basal diet. Young male rats were fed on these diets for respective periods of 10 and 20 days. Concentrations of serum lipids in rats fed on the diets (2), (3) and (4) were compared to those of the control group (diet (1]. Serum total cholesterol level was significantly lower only in the animals fed on DHAconc, whereas serum triglyceride concentration was significantly lower only in the animals fed on EPAconc. Serum phospholipid level was significantly lowered both in the animals fed on either EPAconc or DHAconc. Serum lipid peroxide concentration was elevated in these two groups of animals, while serum alpha-tocopherol concentration was lower in both groups of animals fed on EPAconc and DHAconc, respectively, although these findings were less marked in the rats on the EPAconc diet. From these findings, it is postulated that EPA and DHA have different effects on lipid metabolism in rats with hypercholesterolemia experimentally induced.