British Journal of Nutrition

Full Papers

Metabolism and Metabolic Studies

Marine n-3 fatty acids promote size reduction of visceral adipose depots, without altering body weight and composition, in male Wistar rats fed a high-fat diet

Merethe H. Rokling-Andersena1, Arild C. Rustana2, Andreas J. Wensaasa1, Olav Kaalhusa3, Hege Wergedahla4, Therese H. Røsta4a5, Jørgen Jensena6, Bjørn A. Graffa7, Robert Caesara1 and Christian A. Drevona1 c1

a1 Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Blindern, 0316 Oslo, Norway

a2 Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway

a3 Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway

a4 Institute of Medicine, University of Bergen, Bergen, Norway

a5 Department of Medicine, Haukeland University Hospital, Bergen, Norway

a6 National Institute of Occupational Health, Oslo, Norway

a7 Norwegian Knowledge Centre for the Health Services, Oslo, Norway

Abstract

We evaluated the effects of partly substituting lard with marine n-3 fatty acids (FA) on body composition and weight, adipose tissue distribution and gene expression in five adipose depots of male Wistar rats fed a high-fat diet. Rats were fed diets including lard (19·5 % lard) or n-3 FA (9·1 % lard and 10·4 % Triomar™) for 7 weeks. Feed consumption and weight gain were similar, whereas plasma lipid concentrations were lower in the n-3 FA group. Magnetic resonance imaging revealed smaller visceral (mesenteric, perirenal and epididymal) adipose depots in the n-3 FA-fed animals (35, 44 and 32 % reductions, respectively). n-3 FA feeding increased mRNA expression of cytokines as well as chemokines in several adipose depots. Expression of Adipoq and Pparg was enhanced in the mesenteric adipose depots of the n-3 FA-fed rats, and fasting plasma insulin levels were lowered. Expression of the lipogenic enzymes Acaca and Fasn was increased in the visceral adipose depots, whereas Dgat1 was reduced in the perirenal and epididymal depots. Cpt2 mRNA expression was almost doubled in the mesenteric depot and liver. Carcass analyses showed similar body fat (%) in the two feeding groups, indicating that n-3 FA feeding led to redistribution of fat away from the visceral compartment.

(Received December 08 2008)

(Revised March 02 2009)

(Accepted March 12 2009)

(Online publication April 28 2009)

Correspondence:

c1 Corresponding author: Professor Christian A. Drevon, fax +47 22851393, email c.a.drevon@medisin.uio.no

Footnotes

Abbreviations: AOAC, Association of Official Analytical Chemists; CRP, C-reactive protein; FA, fatty acid; I, intensity; MR, magnetic resonance; MRI, magnetic resonance imaging; ROI, region of interest; TZD, thiazolidinedione

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