Nutritional Studies on Hardened Fish Oil. V.

Effects of Fish Oils with Different Degrees of Hardening on Fatty Acid Profiles of Tissue and Fecal Lipids in Rats

Abstract

Five groups of weanling male rats were maintained on diets containing 20% fish oils with different degrees of hardening supplemented with the minimal linoleate requirement as safflower oil for 28 days. The effects of these fats on liver weight and fatty acid profiles of tissue and fecal lipids were examined. The fats used were an unhardened oil (FO) mainly consisting of sardine oil and four kinds of hardened fats (HFO) obtained stepwise during the hardening process of FO.
1) A transit increase in relative liver weight was observed in both the HFO and the FO groups, and was proportional to the amounts of n-3 polyunsaturated fatty acids in dietary fats.
2) The results of fatty acid analysis of liver and heart lipids indicated the incorporation of n-6 and n-3 polyunsaturated fatty acids in tissue lipids to possibly occur competitively.
3) From analysis of fatty acid compositions of liver, heart and fecal lipids the preferential fecal dischargement of trans-fatty acids, particularly long chain trans-isomers was evident and resumption of the tissue levels of linoleic acid and n-3 polyunsaturated fatty acids was noted to occur easily. The present results agree essentially with those reported previously.