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.
BACKGROUND
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.


OBJECTIVE
To assess the acute metabolic and inflammatory effects of dietary fish oil supplementation on existing postprandial dyslipidaemia in the JCR:LA-cp model.


METHODS
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'.


RESULTS
n-3 PUFA treatment resulted in a significant improvement (i.e. decrease) in the postprandial response for triglyceride (45%) (p < 0.05), apoB48 (45%) (p < 0.03) and LBP (33%) (p < 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%) (p < 0.001) and an increase (i.e. improvement) in adiponectin (33%) (p < 0.05) compared to controls, without a concomitant reduction in food intake.


CONCLUSIONS
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.
Hassanali
Z
Z
Metabolic and Cardiovascular Diseases Laboratory, Alberta Institute for Human Nutrition, University of Alberta, Edmonton, T6G 2P5, Alberta, Canada.
Ametaj
B N
BN
Field
C J
CJ
Proctor
S D
SD
Vine
D F
DF
D000209:Acute-Phase Proteins; D000818:Animals; D053283:Apolipoprotein B-48 / Q000097:blood* / Q000187:drug effects; D015415:Biomarkers / Q000097:blood; D002352:Carrier Proteins / Q000097:blood; D016207:Cytokines / Q000097:blood; D019587:Dietary Supplements; D004195:Disease Models, Animal; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage* / Q000494:pharmacology; D006242:Haptoglobins / Q000378:metabolism; D006949:Hyperlipidemias / Q000097:blood* / Q000188:drug therapy; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood; D009765:Obesity / Q000097:blood* / Q000188:drug therapy; D019518:Postprandial Period; D051381:Rats; D011922:Rats, Mutant Strains; D015430:Weight Gain / Q000187:drug effects; D000099231:Lipopolysaccharide-Binding Protein
D000209:Acute-Phase Proteins; D053283:Apolipoprotein B-48; D015415:Biomarkers; D002352:Carrier Proteins; D016207:Cytokines; D015525:Fatty Acids, Omega-3; D006242:Haptoglobins; D008562:Membrane Glycoproteins; D000099231:Lipopolysaccharide-Binding Protein