EFFECTS OF CONJUGATED LINOLEIC-ACID ON BODY-FAT AND ENERGY-METABOLISMIN THE MOUSE

Conjugated linoleic acid (CLA) is a naturally occurring group of dieno ic derivatives of linoleic acid found in the fat of beef and other rum inants. CLA is reported to have effects on both tumor development and body fat in animal models. To further characterize the metabolic effec ts of CLA, male AKR/J mice were fed a high-fat (45 kcal%) or low-fat ( 15 kcal%) diet with or without CLA (2.46 mg/kcal; 1.2 and 1.0% by weig ht in high- and low-fat diets, respectively) for 6 wk. CLA. significan tly reduced energy intake, growth rate, adipose depot weight, and carc ass lipid and protein content independent of diet composition. Overall , the reduction of adipose depot weight ranged from 43 to 88%, with th e retroperitoneal depot most sensitive to CLA. CLA significantly incre ased metabolic rate and decreased the nighttime respiratory quotient. These findings demonstrate that CLA reduces body fat by several mechan isms, including a reduced energy intake, increased metabolic rate, and a shift in the nocturnal fuel mix.