High fat diets rich in n3 or n6 polyunsaturated fatty acids have distinct effects on lipid profiles and lipid peroxidation in mice selected for either high body weight or leanness

Oxidative stress induced by high fat diets (HFD) and resulting lipid peroxidation have been associated with a range of diseases, such as type 2 diabetes mellitus, arteriosclerosis, Alzheimer disease and cancer. This study investigated the response of mice selected for either high body weight (DU6) obesity prone mice, or high treadmill performance (DUhTP) lean mice, and of unselected control mice (DUK) fed high fat diets rich in n3 or n6 PUFA on muscle lipid peroxidation and fatty acid profile. The isocaloric high fat diets (HFD) were enriched with either n3 PUFA (27 percent fish oil, n3 HFD) or n6 PUFA (27 percent  sunflower oil, n6 HFD), and the control group was fed standard chow (7.2 percent  fat). Statistical calculations were done with procedure GLM of SAS. As expected, the n3 and n6 PUFA rich HFD showed significant effects on fatty acid concentrations of skeletal muscle in all three lines of mice compared with the standard chow. The investigations of muscle lipid peroxidation revealed that the n3 PUFA rich HFD caused the highest lipid peroxidation values in muscle of lean DUhTP mice and unselected control DUK mice. However, lower lipid peroxidation levels were observed in the obesity prone DU6 mice. In contrast, the n6 PUFA rich HFD did not influence lipid peroxidation in muscle of any of the different lines of mice. The data suggest a higher overall antioxidant capacity in muscle tissue of obesity prone DU6 mice may lead to lower levels of ROS formation by n3 PUFA rich HFD in comparison with lean DUhTP mice. This data suggest that a higher overall antioxidant capacity in muscle tissue of obesity prone DU6 mice may lead to a lower level of ROS formation in response to n3 PUFA rich HFD. These studies raise the possibility that obesity per se may be protective against oxidative damage when diets high in n3 PUFA are used. (Authors abstract)