The relationship of single dietary polyunsaturated fatty acids to fatty acid composition of lipids from subcellular particles of liver

Abstract

Supplements of purified fatty acid methyl or ethyl esters were fed at levels of 0.8% of dietary calories to each of seven groups of weanling rats for a period of 60 days. The esters were 9,12-octadecadienoate (18:2) ; 9,12,15-octadecatrienoate (18:3); 10,13-nonadecadienoate (19:2); 5,8,11,14-eicosatetraenoate (20:4); 5,8,11,14,17 - eicosapentaenoate (20:5); 4,7,10,13,16,19-docosahexaenoate (22:6); and 12:13-epoxyoctadeca-9-enoate (epoxyoleate). Rats fed a fat-free diet served as control animals. The effects of these dietary supplements on the fatty acid compositions of the nonphospholipids and phospholipids from liver microsomal and mitochondrial particles, and of unfractionated lipids from liver, testes, epididymal, and heart tissues were determined by gas–liquid chromatography.Epoxyoleate and 19:2, which are structurally related to linoleic acid, did not function as essential fatty acids as judged by the chemical and biological symptoms of fat deficiency. Dietary 20:5 and 22:6, both related to linolenate, were less active than linoleate in preventing the biological symptoms of fat deficiency, but more active in depressing the content of eicosatrienoate. Docosapentaenoic acid of the linoleate family was identified by reductive ozonolysis and shown to increase with an increase in dietary 18:2 or 20:4.