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ABSTRACT: The purpose of this study was to evaluate whether conjugated linoleic acid (CLA) exposure during the developmental period increases voluntary activity, which would influence obesity outcome later in life. The effects of dietary supplementation of 0.5% CLA in a high fat diet were evaluated in nescient basic helix-loop-helix 2 (Nhlh2) knock-out (N2KO) mice, which is a unique animal model representing inactivity-induced obesity in a pre-obese condition. Male wild type and N2KO mice were fed either control or CLA (0.5%) diet for 8 weeks. As expected, control diet fed N2KO animals showed greater body weight with decreased physical activity in the late stage of the experimental period compared with wild type control. Dietary CLA significantly decreased body weight and adipose depots in both wild type and N2KO mice, and the body weights of both genotypes fed CLA were similar during the experimental period. CLA exposure during the developmental period significantly improved the impairment of physical activity in N2KO mice, but the wild type did not show any effect of CLA. In both genotypes, CLA significantly reduced serum triglycerides levels and down-regulated the mRNA expressions of CCAAT/enhancer binding protein α (C/EBPα) and leptin in white adipose tissue. These findings suggest that early CLA exposure could prevent obesity with improved voluntary physical activity in N2KO mice.
Food & function. 09/2012;
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ABSTRACT: Conjugated linoleic acid (CLA) has been extensively studied during the last two decades with regard to its effects on controlling body composition. As a cognate to CLA, conjugated nonadecadienoic acid (CNA) has been previously reported to reduce body fat more effectively than CLA. However, it is not known whether CNA supplementation can influence adult-onset obesity. Thus, the purpose of this study was to evaluate the effects of dietary CNA on the prevention of adult-onset inactivity-induced obesity using nescient basic helix-loop-helix 2 knockout (N2KO) mice. CNA supplementation at 0.1w/w% level starting in the preobese state significantly prevented the reduction of voluntary movement and the increase in weight gain in N2KO mice during the experimental period compared to wild-type animals. In both wild-type and N2KO mice, respiratory exchange ratio was significantly reduced by CNA treatment during light and dark cycles, and dietary CNA significantly increased energy expenditure in N2KO mice. Selected gene expression profiles in white adipose tissue, muscle or liver showed a beneficial action of CNA on lipid metabolism and energy expenditure. These findings suggest that CNA could prevent adult-onset obesity by enhancing voluntary activity and energy expenditure in N2KO mice.
The Journal of nutritional biochemistry 07/2012; · 4.29 Impact Factor
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ABSTRACT: The supplementation of conjugated linoleic acid (CLA) has been shown to improve endurance by enhancing fat oxidation during exercise in rodents and humans. This study was designed to investigate the isomer-specific effects of CLA on endurance capacity and energy metabolism in mice during exercise. Male 129Sv/J mice were divided into three dietary groups and fed treatment diet for 6 weeks; control, 0.5 % cis-9,trans-11 (c9,t11) CLA, or 0.5 % trans-10,cis-12 (t10,c12) CLA. Dietary t10,c12 CLA induced a significant increase in maximum running time and distance until exhaustion with a dramatic reduction of total adipose depots compared to a control group, but there were no significant changes in endurance with the c9,t11 CLA treatment. Serum triacylglycerol and non-esterified fatty acid concentrations were significantly lower in the t10,c12 fed mice after exercise compared to control and the c9,t11 CLA fed-animals. Glycogen contents in livers of the t10,c12 fed-mice were higher than those in control mice, concomitant with reduction of serum L-lactate level. There were no differences in non-exercise physical activity among all treatment groups. In addition, the mRNA expression levels of carnitine palmitoyl transferase 1β, uncoupling protein 2 and peroxisome proliferator-activated receptor δ (PPARδ) in skeletal muscle during exercise were significantly up-regulated by the t10,c12 CLA but not the c9,t11 CLA. These results suggest that the t10,c12 CLA is responsible for improving endurance exercise capacity by promoting fat oxidation with a reduction of the consumption of stored liver glycogen, potentially mediated via PPARδ dependent mechanisms.
Lipids 07/2012; 47(9):855-63. · 2.13 Impact Factor
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ABSTRACT: It is well established that the lack of physical activity can lead to weight gain or obesity. However, there is limited information on influences of diet components on physical activity. Thus the purpose of this study was to investigate the role of major dietary components on energy expenditure by affecting nonexercise physical activity in C57BL/6J mice. All mice were assigned to 1 of the following 4 dietary groups based on their body weight and baseline physical activity; low fat/normal protein, high fat/normal protein, low fat/low protein, or low fat/high protein. After 3 mo, the highest weight gain was observed in animals fed with high-fat/normal-protein diet, and the caloric intake was significantly lower in low-fat/high-protein diet-fed mice compared to other groups. However, there were no significant changes in nonexercise physical activity during experimental periods in all groups. The respiratory quotient and energy expenditure were not significantly different among the dietary groups. These findings suggest that diet-induced obesity is not explainable by levels of physical activity and energy expenditure. PRACTICAL APPLICATION: The understanding the link between diet and nonexercise physical activity would provide important knowledge that will potentially assist appropriate food choices to control obesity and its related health problems.
Journal of Food Science 02/2012; 77(2):H63-8. · 1.66 Impact Factor
