Effect of Dietary Eicosapentaenoic Acid on Serum and Liver Lipids Patterns of Male Rat

어유의 Eicosapentaenoic Acid의 식이섭취가 성숙쥐의 혈청 및 간의 지질조성에 미치는 영향

The dietry effects of marine n-3, plant n-3 and plant n-6 fatty acid on serum lipids levels, liver phospholipid fatty acid composition in rat were investigated. Four groups of male Sprague-Dawley rats, 30 weeks old, were fed on one of 4 different experimental diets for 4 weeks. The diets were composed of 15% fat(w/w) of either concentrated EPA oil(20:5, n-3 : 65%), fish oil(20:5, n-3 : 19%, 22:6, n-3 : 18%), perilla oil(18:3, n-3 : 60%) or corn oil(18:2, n-6 : 49%). Blood was initially taken before experimental feeding and also taken after 2 weeks and 4 weeks feeding the diet respectively and then examined for the levels of serum lipids. Rats were sacrificed at 4 weeks after the diet for the analysis of liver phospholipid fatty acid. EPA feeding remarkably decreased the serum levels of triglyceride, total cholesterol, HDL-cholesterol and total phospholipid than any other oil feeding. Fish oil feeding decreased serum HDL-cholesterol level comparable to the effect of EPA feeding and decreased total cholesterol and phospholipid less than but close to the effect of EPA feeding. Perilla oil feeding did not change serum levels of triglyceride and phospholipid, but it decreased serum total cholesterol a lot and HDL-cholesterol a little. Corn oil feeding did not affect triglyceride and total cholesterol while it increased serum level of HDL-cholesterol and total phospholipid. Serum HDL-cholesterol level was increased only in corn oil group. But contrary to the result of serum total phospholipid, liver phospholipid level found to be higher in fish oil and EPA groups than in perilla oil and corn groups. The fatty acid composition of liver phospholipid, phosphatidylcholine(PC) and phosphatidyl ethanolamine(PE) turned out to be affected by dietary fatty acid. 18:2 of liver PC was the lowest in FO group following CO group. The ratio of 20:4/18:2 was lower in PO group than in EPA group in consequence of higher 18:2 and lower 20:4 in PO group and vise versa in EPA group. In the liver PC and PE, similar trends in the ratios of n-6/n-3 and 20:4/18 were found showing higher ratios with CO and EPA group over FO and PO group. EPA group showed the lowest level of 20:5 and lower level of 20:6 than group. Fish oil was more efficient than EPA oil and PO in lowering the ratio of n-6/n-3 in consequence of the highest 22:6, and the lowest 18:2 in liver phospholipid. But PO lowers the ratio or 20:4/18 more than FO. In conclusion, EPA oil was more effective in lowering serum lipids than FO and PO. Reviewing the dietary effect of fatty acid on eicosanoids composition in rats, it is considered that more possibility was with FO than PO in the effectiveness of atherosclerosis prevention and more with PO than with EPA oil. It was also found that FO showed more effective than EPA oil for atherosclerosis prevention. It was hardly found that CO had any effect on lowering serum lipids and on eicosanoids composition in liver phospholipid for the prevention of atherosclerosis.