[Comparison of mean-term physiological effects of cis and trans docosenoic acids in the rat. II. Effects on the lipids and fatty acids of plasma, adipose tissue, liver and heart].

The mean term effects (16 weeks) of brassidic acid (n-9 trans docosenoic acid) and erucic acid (n-9, cis docosenoic acid) on the lipids and fatty acids of different organs in the rat (plasma, adipose tissue, liver, heart) and compared to those of their C 18 homologues, elaidic and oleic acid, in a 2(3) factorial experiment; the three tested factors are: 1) the chain length of the dietary monoenes (C 22:1 vs. C 18:1), 2) the geometrical configuration of their double bond (trans vs. cis) and 3) the dietary levels (30% vs. 1,7% of dietary fatty acids). Experimental details have been reported previously [Astorg and Levillain, 1979]. With a low supply of linoleic acid, brassidic acid, brassidic acid induces a large increase of plasma triacylglycerols (TG), but this can be caused by a slow fat absorption. However, the plasma contents of cis and trans docosenoic acids do not differ greatly. Both docosenoic acids incorporate more into the lipids of heart and adipose tissue than into liver lipids, and, for each organ, more into TG than into phospholipids (PL). In heart and adipose tissue lipids, the percentage of brassidic acid is lower than that of erucic acid. In these 2 organs and in the liver, linoleic acid subdeficiency decreases the incorporation of both C 22:1 isomers into the lipids. Dietary brassidic acid is readily converted to other trans monoenes, mainly elaidic acid, which incorporates into organ lipids. The extent of this chain-shortening may be greater than that of erucic acid (to oleic acid), and this would explain the lower level of brassidic acid found in organ lipids. Last, dietary trans monoenes (brassidic and elaidic acids) induce, as compared to their cis isomers, slight but visible changes in the profile of (n-9) polyunsaturated fatty acids in organ lipids. These results are discussed and related to the fact that brassidic acid does not seem to have the heart pathogenic potency of erucic acid [see part 1 of this paper, Astorg and Levillain, 1979].