Effect of conjugated FA on feed intake, body composition, and liver FA in mice

CLA is a generic term describing different isomers of linoleic acid with two conjugated double bonds. Various metabolic effects have been demonstrated following administration of CLA, including a change in body composition in animals. However, the effects of pure CLA isomers are not fully understood. In addition, conjugated octadecatrienoic acids such as calendic acid have not been extensively investigated. In this study, male and female ICR mice were fed pure CLA isomers (cis 9, trans 11 or trans 10,cis 12) or calendic acid (trans 8,trans 10, cis 12) as their ethyl esters for 6 wk. Body protein content was significantly increased after feeding CLA isomers, either as pure isomers or as a mixture. Calendic acid significantly decreased body fat content in males. CLA (pure isomers or a mixture) significantly decreased body fat in both males and females, with the trans 10, cis 12 isomer being the most effective. The effect of the cis 9, trans 11 isomer was more pronounced in females than in males. It was concluded that the trans 10, cis 12 CLA isomer was mainly responsible for the decrease in fat content in mice, without a significant modification of feed efficiency, and that it was more effective than calendic acid.