| Research Abstract |
The present study explored the effect of CLA supplementation in semisynthetic diets on body fat accumulation and lipid metabolism in male OLETF rats. Feeding rats both TAG-CLA and FA-CLA significantly lowered the weights of abdominal adipose tissues (perirenal, epididymal and omental) and the concentrations of TAG in the liver and serum, compared to the OLETF control group. This was associated with enhanced CPT activity in muscle, BAT, WAT and liver, suggesting that CLA increases fatty acid beta-oxidation. TAG-CLA had no significant effects on serum insulin and glucose levels, whereas FA-CLA induced higher serum glucose levels without affecting insulin level. When rats were fed either 9c,11t-CLA, 10t,12c-CLA or linoleic acid (control) at the 1% level, significant reductions in abdominal fat weight and serum and hepatic TAG levels were demonstrated in the 10t,12c-CLA group, but not in the 9c,11t-CLA group, as compared with control group. The 10t,l2c-CLA group exhibited higher activity and mRNA expression of CPT, lower activity and mRNA expression of fatty acid synthase, and lower SREBP-1c mRNA expression. Oxygen consumption and energy expenditure, were significantly higher in the 10t, 12c-CLA group than in the 9c,11t-CLA group. These results indicate that the10t,12c-CLA isomer is responsible for the fat-lowering activity and the enhancement of energy metabolism in OLETF obese rats.
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