Dietary supplementation of n‐3 PUFA reduces weight gain and improves postprandial lipaemia and the associated inflammatory response in the obese JCR:LA‐cp rat

<jats:p> <jats:bold>Background:</jats:bold> Postprandial dyslipidaemia occurs in obesity and insulin resistance (IR), and is associated with an increased risk of developing cardiovascular disease. We have recently established that the JCR:LA‐cp rodent model develops postprandial dyslipidaemia concomitant with complications of the metabolic syndrome. Dietary n‐3 polyunsaturated fatty acids (n‐3 PUFAs) are proposed to modulate plasma lipids, serum hormone levels, lipoprotein metabolism and the inflammatory state; however, results remain inconsistent during conditions of IR.</jats:p><jats:p> <jats:bold>Aim:</jats:bold> To assess the acute metabolic and inflammatory effects of dietary fish oil supplementation on existing postprandial dyslipidaemia in the JCR:LA‐cp model.</jats:p><jats:p> <jats:bold>Methods:</jats:bold> JCR:LA‐cp rats (14 weeks of age) were fed either a control, isocaloric, lipid balanced diet (15% w/w total fat, 1.0% cholesterol, P:S ratio 0.4), a lipid balanced diet with 5% n‐3 PUFA [fish oil derived eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA)] or a lipid balanced diet with 10% n‐3 PUFA for 3 weeks. Fasting plasma lipid, cytokine levels, postprandial chylomicron (apoB48) metabolism and the postprandial inflammatory response [haptoglobin and lipopolysaccharide binding protein (LBP)] were assessed following a standardized ‘oral fat challenge’.</jats:p><jats:p> <jats:bold>Results:</jats:bold> n‐3 PUFA treatment resulted in a significant improvement (i.e. decrease) in the postprandial response for triglyceride (45%) (<jats:italic>p</jats:italic> < 0.05), apoB48 (45%) (<jats:italic>p</jats:italic> < 0.03) and LBP (33%) (<jats:italic>p</jats:italic> < 0.05) compared to controls (measured as area under the clearance curve). In contrast, we observed a significant elevation in postprandial haptoglobin (165%) (p < 0.001) in obese rats supplemented with 10% n‐3 PUFA. Treatment with 5% n‐3 PUFA in the JCR:LA‐cp obese animals resulted in a complementary decrease in total body weight gain (6%) (<jats:italic>p</jats:italic> < 0.001) and an increase (i.e. improvement) in adiponectin (33%) (<jats:italic>p</jats:italic> < 0.05) compared to controls, without a concomitant reduction in food intake.</jats:p><jats:p> <jats:bold>Conclusion:</jats:bold> Acute dietary n‐3 PUFA dietary supplementation can improve fasting as well as postprandial lipid metabolism and components of the associated inflammatory response in the JCR:LA‐cp rat. Further, moderate dose n‐3 PUFA supplementation may reduce corresponding body weight during conditions of hypercholesterolaemia and/or modulate inflammation associated with obesity and the metabolic syndrome.</jats:p>