Modulation of body fat and serum leptin levels by dietary conjugated linoleic acid in Sprague-Dawley rats fed various fat-level diets

OBJECTIVES: In this study, we examined the effect of dietary conjugated linoleic acid (CLA) on body fat levels in Sprague-Dawley rats. Methods: Rats were fed AIN-93G type diets containing 4%, 7%, and 10% fats with or without 1.5% CLA. Results: Three weeks after the onset of the experimental period, the weights of perirenal white adipose tissue were lower in CLA-fed rats. The weights of epididymal white adipose tissue also were lower in CLA-fed rats than in control rats, but this effect disappeared with increased dietary fat level. Serum leptin levels tended to be lower in the CLA group, especially the low-fat diet group, than in the control group. There were significant positive correlations between serum leptin level and weights of perirenal and epididymal white adipose tissues in control groups, but these correlations were weaker in the CLA groups. Serum tumor necrosis factor-α levels also tended to be lower in CLA-fed rats, and this tendency was most remarkable in the rats fed 7% fat diets. Conclusions: In conclusion, dietary CLA, especially the low-fat diet, reduced body fat without hepatic injury to Sprague-Dawley rats.