Effect of fish oil on plasma lipoproteins, liver glucose-6-phosphate dehydrogenase and glucose-6-phosphatase in rats.

To investigate the effect of dietary fish oil on the lipid and glucose metabolism, Wistar rats were fed lard (10% fat by weight) or fish oil (5% lard + 5% fish oil) diet for 7 weeks. Significantly (p < 0.05) lower plasma total cholesterol, low density lipoprotein cholesterol (VLDL-C) levels were observed in rats fed a diet containing fish oil when compared with rats fed lard diet. Fish oil supplementation decreased plasma lactic acid and free fatty acid levels. In addition, lower plasma lactate dehydrogenase (LDH) activity and an improved glucose tolerance ability were observed in rats fed fish oil diet. However, no significant change in plasma glucose level was found in rats between the two dietary groups. Although rats fed a diet containing fish oil had significantly (p < 0.05) decreased total cholesterol and phospholipid contents in the liver, there was no significant difference in liver triglyceride content between the two dietary groups. It is interesting to note that fish oil supplement significantly (p < 0.05) decreased liver glucose-6-phosphate dehydrogenase (G-6-PDH) and glucose-6-phosphatase (G-6-Pase) activities. Results from the present study suggest that dietary n-3 polyunsaturated fatty acids might play an important role in regulation of glucose and lipid metabolism in rats.