TRIACYLGLYCEROL COMPOSITION OF ADIPOSE-TISSUE, MUSCLE AND LIVER OF RATS FED DIETS CONTAINING FISH OIL OR CORN-OIL

The effect of dietary fish oil and corn oil on the fatty acid composition of triacylglycerol in adipose tissue, muscle and liver was studied for a period of seven weeks in young, growing rats. In all tissues, three fatty acids, palmitic (16:0), oleic (18:1, n-9) and linoleic (18:2, n-6) accounted for approximately 85% of the fatty acids in corn oil-fed and 65% in fish oil-fed rats. Eicosapentaenoic acid (20:5, n-3, EPA) and docosahexaenoic acid (22:6, n-3, DHA) were very low or undetectable in animals consuming corn oil. In rats consuming fish oil, these fatty acids each accounted for approximately 4% of the fatty acids present. However, in liver these two fatty acids accounted for about 25% of the triacylglycerol fatty acids by week two which declined to about 11% by week seven. Interestingly, in all tissues, EPA was underrepresented relative to DHA compared with their content in the diet. This suggests that there is either selective utilization of EPA or selective retention of DHA. The results confirm the effect of diet fatty acid composition on triacylglycerol composition and show clearly that long chain n-3 fatty acids are efficiently stored in triacylglycerol deposits of tissues.