| Summary: | <p>Abstract</p> <p>Background</p> <p>Conjugated linoleic acid (<it>cis</it>-9, <it>trans</it>-11 CLA) and <it>trans</it>-11 vaccenic acid (VA) are found naturally in ruminant-derived foods. CLA has been shown to have numerous potential health related effects and has been extensively investigated. More recently, we have shown that VA has lipid-lowering properties associated with reduced hepatic lipidogenesis and chylomicron secretion in the JCR:LA<it>-cp </it>rat. The aim of this study was to evaluate potential additional hypolipidemic effects of purified forms of CLA and VA in an animal model of the metabolic syndrome (the JCR:LA-<it>cp </it>rat).</p> <p>Methods</p> <p>Twenty four obese JCR:LA-<it>cp </it>rats were randomized and assigned to one of three nutritionally adequate iso-caloric diets containing 1% w/w cholesterol and 15% w/w fat for 16 wk: 1) control diet (CD), 2) 1.0% w/w <it>cis</it>-9, <it>trans</it>-11 CLA (CLA), 3) 1.0% w/w VA and 1% w/w <it>cis</it>-9, <it>trans</it>-11 CLA (VA+CLA). Lean rats were fed the CD to represent normolipidemic conditions.</p> <p>Results</p> <p>Fasting plasma triglyceride (TG), total cholesterol and LDL-cholesterol concentrations were reduced in obese rats fed either the CLA diet or the VA+CLA diet as compared to the obese control group (p < 0.05, p < 0.001; p < 0.001, p < 0.01; p < 0.01, p < 0.001, respectively). The VA+CLA diet reduced plasma TG and LDL-cholesterol to the level of the normolipidemic lean rats and further decreased nonesterified fatty acids compared to the CLA diet alone. Interestingly, rats fed the VA+CLA diet had a higher food intake but lower body weight than the CLA fed group (P < 0.05). Liver weight and TG content were lower in rats fed either CLA (p < 0.05) or VA+CLA diets (p < 0.001) compared to obese control, consistent with a decreased relative protein abundance of hepatic acetyl-CoA carboxylase in both treatment groups (P < 0.01). The activity of citrate synthase was increased in liver and adipose tissue of rats fed, CLA and VA+CLA diets (p < 0.001) compared to obese control, suggesting increased mitochondrial fatty acid oxidative capacity.</p> <p>Conclusion</p> <p>We demonstrate that the hypolipidemic effects of chronic <it>cis</it>-9, <it>trans</it>-11 CLA supplementation on circulating dyslipidemia and hepatic steatosis are enhanced by the addition of VA in the JCR:LA-<it>cp </it>rat.</p>
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