Incorporation of conjugated linoleic acid into mouse tissues and the regulation of feed intake and body fat in the short term

Abstract

Conjugated linoleic acid (CLA) is known to decrease feed intake and body fat in mice. Our objectives were to determine the incorporation of CLA into tissues and the effect on serum hormones during the first 7 d of CLA consumption. Mice (n=150; 9‐wk‐old) were fed 0 (ad libitum or pair‐fed to CLA‐fed mice) or 2% CLA (ad libitum) for 1, 2, 3, 5, or 7 d. A body fat index was calculated; liver, adipose tissue, and brain were analyzed for fatty acid profiles; and serum insulin, leptin, and PYY were measured. CLA and pair‐fed mice ate less (P < 0.05) than control mice on d 1, 2, 3, and 7, but CLA‐fed mice were leaner than control and pair‐fed mice only on d 7 (P < 0.01). CLA was detected in adipose tissue starting on d 2 and in liver on d 1, but CLA was not detectable in the brain. Serum insulin tended (P = 0.11 and 0.13, respectively) to be increased in CLA‐fed mice on d 5 and 7, and serum leptin was non‐significantly reduced in CLA‐fed mice compared to control mice on d 7. The CLA‐induced reduction in feed intake was not sufficient to cause the loss of body fat as pair‐fed mice were not leaner than controls. The lack of CLA in the brain indicates that the effect on feed intake may be indirect.