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A CLA Mixture Prevents Body Triglyceride Accumulation without Affecting Energy Expenditure in Syrian Hamsters

Bouthegourd, Jean-Christophe, Even, Patrick C., Gripois, Daniel, Tiffon, Bernard, Blouquit, Marie-France, Roseau, Suzanne, Lutton, Claude, Tomé, Daniel, Martin, Jean-Charles
Journal of nutrition 2002 v.132 no.9 pp. 2682-2689
adiposity, basal metabolic rate, carbohydrates, carnitine palmitoyltransferase, conjugated linoleic acid, dietary protein, energy metabolism, exercise, golden hamsters, insulin, insulin resistance, isomers, leptin, lipid peroxidation, nuclear magnetic resonance spectroscopy, proteins, triiodothyronine
We examined the effects of feeding conjugated linoleic acids (CLA) to adult male hamsters on several components of energy metabolism and body composition. Hamsters (n = 54) were assigned for 6-8 wk to one of three diets: 1) a standard diet (in percentage energy: lipids, 33, carbohydrates, 49, and proteins, 18); 2) to the standard diet augmented with the 9c,11t-isomer of CLA to 1.6% of energy (R group); or 3) the standard diet augmented with the 9c,11t-isomer and the 10t,12c-CLA isomer to 3.2 (1.6 + 1.6) % of energy (CLA mix group). 15N uniformly labeled milk-protein was included in the diet to measure the incorporation of dietary protein into liver and muscle. Basal metabolic rate, thermogenic response to feeding and energy expenditure during spontaneous activity or during an exercise at ∼60% of Vo(2max) were measured. Carnitine palmitoyltransferase-I (CPT-I), leptin, insulin and triiodothyronine concentrations, as well as the in vivo overall adiposity changes were also determined. After 6 wk, the whole-body triglyceride content determined in vivo by NMR was significantly higher in the R group than in the control and CLA mix groups. The CLA mix group differed from the others in the lack of body triglyceride accumulation between d 21 and d 45 of the study, and the appearance of a slight insulin-resistance (homeostatic model assessment index, P < 0.05). Paradoxically, the lack of effect on whole-body lipid oxidation was associated with a greater CPT-I-specific activity in tissues of both CLA-fed groups (P < 0.05). No other major effects of CLA feeding were detected. In conclusion, CLA supplementation in hamsters did not affect adipose weight or the components of energy expenditure despite a theoretically higher capacity of red muscle to oxidize lipids. Only a CLA mixture prevented whole-body triglyceride accumulation over time.