Effects of cis-9,trans-11 and trans-10,cis-12 CLA isomers on liver and adipose tissue fatty acid profile in hamsters.

The aim of the present study was to investigate the effect of cis-9,trans-11 and trans-10,cis-12 CLA on FA composition of TAG in epididymal adipose tissue and liver, and of hepatic phospholipids PL. Twenty-four Syrian Golden hamsters were randomly divided into three groups of eight animals each and fed semipurified atherogenic diets supplemented with either 0.5 g/100 g diet of linoleic acid or cis-9,trans-11 or trans-12,cis-9 CLA for 6 wk. Total lipids were extracted, and TAG and PL were separated by TLC. FA profile in lipid species from liver and adipose tissue, as well as in feces, was determined by GC. Trans-10,cis-12 CLA feeding significantly reduced linoleic and linolenic acids in TAG from both tissues, leading to reduced total PUFA content. Moreover, in the epididymal adipose tissue docosenoic and arachidonic acids were significantly increased. In liver PL, although no changes in individual FA were observed, total saturated FA (SFA) were decreased. No changes in TAG and PL FA profiles were induced by the cis-9,trans-11 CLA. TAG and PL incorporated cis-9,trans-11 more readily than trans-10,cis-12 CLA. This difference was not due to differential intestinal absorption, as shown by the analysis of feces. We concluded that only trans-10,cis-12 CLA induces changes in FA composition. Whereas increased PUFA content was observed in either liver or adipose tissue TAG, decreased SFA were found in liver PL. Incorporation of cis-9,trans-11 CLA in TAG is greater than that of trans-10,cis-12 CLA, but this is not due to differences in intestinal absorption.