Effects of Supplemented Diacylglycerol Rich in Docosahexaenoic Acid on Serum Triacylglycerol in a Diet-Induced Hyperlipidemic Model of Rats Are Essentially Equivalent to Those of Triacylglycerol Rich in Docosahexaenoic Acid

Abstract

Effects of supplemented docosahexaenoic acid (DHA), given as diacylglycerol (DG) rich in DHA (DHA-DG), triacylglycerol (TG) rich in DHA (DHA-TG) or fish oil concentrate (DHA-70), on the serum concentration of TG and its bioavailability in the rats with diet-induced hyperlipidemia were studied. Hypertriglyceridemia was induced by feeding male Wistar rats a semi-purified diet that contained 5% corn oil and 50% sucrose by weight. In addition to the feeding of dietary corn oil, the rats received DHA intragastrically at a dose of 500 mg/kg body weight once a day for 28 d and the control rats were given olive oil. The serum concentration of TG in the rats that received DHA-DG was significantly lower than in the control rats. However, there were no significant differences in diet intake, energy intake, body weight gain, visceral fat mass or fecal excretion of total fatty acids among the four groups. The amounts of DHA excreted into the feces of the three groups of rats that received DHA were approximately 0.4% of the DHA administered. The extent of the decreases induced by DHA-DG in the serum level of TG was almost the same as those induced by DHA-TG and DHA-70. The administration of DHA, regardless of the differences in molecular structure, did not affect the hepatic contents of TG or phospholipid. The administration of DHA-DG considerably increased the proportions of DHA and eicosapentaenoic acid (EPA) while decreasing the proportion of arachidonic acid in hepatic lipids, and as a result in the lipids in serum and erythrocytes, to the same extents as did DHA-TG and DHA-70. These results suggest that the hypotriglyceridemic effects and bioavailability of DHA when supplemented in the form of DG are essentially equivalent to those of DHA-TG and DHA-70.