MODIFICATION OF RAT PLATELET FATTY-ACID COMPOSITION BY DIETARY LIPIDS OF ANIMAL AND VEGETABLE ORIGIN

There were no statistically significant differences in final body weight or in food intake among groups of rats fed for 7 wk various fat of animal origin (lard fat and cod liver oil) or vegetable origin (corn, soybean and canola oils); the fats were fed as 10% of the diet (by wt) and were of varied fatty acid composition. Nevertheless, the mean weights of the kidneys from cod liver oil-fed animals were significantly higher than those of all other dietary groups. Platelets of rats from the groups receiving the animal fat contained significantly lower levels of linoleic acid, 18:2(n-6) [a precursor of arachidonic acid, 20:4(n-6)], than did platelets from rats receiving the fat of vegetable origin. Although the soybean-, canola- and cod liver oil-fed animals received substantial quantities of (n-3) fatty acids [α-linolenic acid, 18:3(n-3); eicosapentaenoic acid, 20:5(n-3); and docosahexaenoic acid, 22:6(n-3)], only the platelets of the latter two groups contained detectable levels of these fatty acids along with their products of elongation/desaturation/retroconversion. Platelets of the cod liver oil-fed group contained significantly less arachidonic acid, a major precursor of eicosanoids, than did those from all other dietary groups. However, platelet arachidonic levels also varied markedly among the other dietary groups. Diet-induced fatty acid changes observed in platelets of various dietary groups may influence platelet responses, including secretion, aggregation and biosynthesis of eicosanoids.