Relationship between the Effect of Dietary Fat on Swimming Endurance and Energy Metabolism in Aged Mice

Abstract

Aim: The aim of this study was to investigate the effect of different dietary fats on alterations in endurance, energy metabolism, and plasma levels of interleukin-6 (IL-6) and minerals in mice. Method: Male mice (aged 58 weeks) were fed diets containing 6% safflower oil, fish oil, or lard for 12 weeks. Swimming time to exhaustion, energy metabolism, and plasma IL-6 levels were subsequently determined. Results: Mice fed safflower oil exhibited a marked increase in swimming time compared to the baseline level. Mice fed lard exhibited a significant decrease in swimming time, while mice on a fish oil diet exhibited a small decrease in swimming time. The final swimming time of mice fed safflower oil was significantly longer than that of animals fed lard. This improvement in endurance with dietary safflower oil was accompanied by decreased accumulation of lactate and less glycogen depletion during swimming. In the safflower oil group, muscle carnitine palmitoyltransferase activity increased significantly after swimming, while the plasma non-esterified fatty acid concentration decreased significantly. A trend to increased plasma IL-6 levels was observed in sedentary animals on a safflower oil diet compared to those on a lard diet. Conclusions: These results suggest that dietary safflower oil improves the swimming endurance of aged mice to a greater extent than lard, and that this effect appears to involve glycogen sparing through increased fatty acid utilization.