The study was to compare the effect of dietary fatty acids on fatty acid profile in tissue and the status of tocopherol an lipid peroxidation, and superoxide dismutase and glutathione peroxidase activities at two fat levels. Male Spragtue Dawley
rats
weighing average 350g(17 weeks) were fed either low fat(LF, 4.3% w/w, 10% kcal) or high fat (HF, 20.8% w/w, 40%) kcal) diet for 6 weeks. The fats used were beef tallow as a source of saturated fatty acid, corn on for n-6 linoleic acid, perilla
oil
for
n-3 α-linolenic acid and fish oil for n-3 eicosapentaenoic acid(EPA) and n-3 docosahexaenoic acid(DHA).
Plasma tocopherol was significantly reduced by fish oil compared to beef tallow at both fat level. However, there was no significant effect on the levels of plasma MDA, RBC MDA and tocopherol, and RBC hemolysis by the type and amount of dietary
fat. The
peroxidizibility index of fatty acid profile in plasma and liver was increased and liver MDA level was significantly increased by fish oil when dietary fat levels was increased. the activities of SOD and GSH-Px tended to be increased by perilla
oil
and
fish oil at both fat level., but it could not prevent the lipid peroxidation in tissue at high fat diet. Perilla oil and fish oil significantly reduced the incorporation of c20 : 4 and increased the incorporation of c20 : 4 ad increased the
incorporation of c20 : 5 into liver compared to corn oil. The incorporation of n-3 fatty acids into tissue by perilla oil rich in α-linolenic acid was significantly higher than corn oil and its effect was improved with higher amount of perilla
oil
in
diet by higher fat diet.
Overall, the lipid peroxidation of tissue could be prevented by tocopherol supplementation when dietary fat level was low in diet. However, at high fat diet, tocopherol supplementation.might not be enough to prevent the lipid peroxidation in
tissue
since the potential for lipid peroxidation was tended to be increased with higher incorporation of highly unsaturated n-3 fatty acids into tissue. Therefore, it could not be recommended to consume large amount of fish oil even with excess amount
of
tocopherol supplemented to the high fat diet.
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