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Journal of Nutrition and Metabolism
Volume 2012, Article ID 268680, 12 pages
http://dx.doi.org/10.1155/2012/268680
Research Article

Exercise and Omega-3 Polyunsaturated Fatty Acid Supplementation for the Treatment of Hepatic Steatosis in Hyperphagic OLETF Rats

1Departments of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65201, USA
2Division of Animal Sciences, University of Missouri, Columbia, MO 65201, USA
3Internal Medicine-Division of Gastroenterology, University of Missouri, Columbia, MO 65201, USA
4Harry S Truman Memorial Veterans Hospital, Research Service, Columbia, MO 65201, USA
5Food Science-Division of Food Systems & Bioengineering, University of Missouri, Columbia, MO 65201, USA
6Department of Biomedical Sciences, University of Missouri, Columbia, MO 65201, USA
7Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65201, USA
8Dalton Cardiovascular Center, University of Missouri, Columbia, MO 65201, USA

Received 9 June 2011; Accepted 11 July 2011

Academic Editor: Jean-Marc Lavoie

Copyright © 2012 Sarah J. Borengasser et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background and Aims. This study examined if exercise and omega-3 fatty acid (n3PUFA) supplementation is an effective treatment for hepatic steatosis in obese, hyperphagic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Methods. Male OLETF rats were divided into 4 groups ( 𝑛 = 8 /group): (1) remained sedentary (SED), (2) access to running wheels; (EX) (3) a diet supplemented with 3% of energy from fish oil (n3PUFA-SED); and (4) n3PUFA supplementation plus EX (n3PUFA+EX). The 8 week treatments began at 13 weeks, when hepatic steatosis is present in OLETF-SED rats. Results. EX alone lowered hepatic triglyceride (TAG) while, in contrast, n3PUFAs failed to lower hepatic TAG and blunted the ability of EX to decrease hepatic TAG levels in n3PUFAs+EX. Insulin sensitivity was improved in EX animals, to a lesser extent in n3PUFA+EX rats, and did not differ between n3PUFA-SED and SED rats. Only the EX group displayed higher complete hepatic fatty acid oxidation (FAO) to CO2 and carnitine palmitoyl transferase-1 activity. EX also lowered hepatic fatty acid synthase protein while both EX and n3PUFA+EX decreased stearoyl CoA desaturase-1 protein. Conclusions. Exercise lowers hepatic steatosis through increased complete hepatic FAO, insulin sensitivity, and reduced expression of de novo fatty acid synthesis proteins while n3PUFAs had no effect.