Effects of Dietary Fatty Acid Composition on Pro -and Macro -Glycogen Utilization and Resynthesis in Rat Skeletal Muscle

ABSTRACT

The purpose of this study was to investigate that the effect of dietary fatty acid composition on pro- and macro-glycogen utilization and resynthesis. The analyses were further extended for different muscle fibers (type I, type II, & type IIb ) as well as tissues (i.e., liver & heart ). Total one hundred sixty Sprague-Dawley rats were used, and rats were randomly allocated into four experimental groupsanimals fed standard chow diet (n =40 ), animals fed saturated fatty acid diet (n =40 ), animals fed monounsaturated fatty acid (n =40 ), and animals fed polyunsaturated fatty acid (n =40 ). Animals in each groups were further divided into five subgroupssacrificed at REST (n =8 ), sacrificed at immediately after 3 hr swim exercise (P-0HR, n =8 ), sacrificed at one hour after 3 hr swim exercise (P-1HR, n =8 ), sacrificed at four hour after 3 hr swim exercise (P-4HR, n =8 ), and sacrificed at twenty-four hour after 3 hr swim exercise (P-24HR, n =8 ). Soleus (type I ), red gastrocnemius (type IIa ), white gastrocnemius (type IIb ), liver, and heart were dissected out at appropriated time point from all animals, and were used for analyses of pro- & macro-glycogen concentrations. After 8 weeks of dietary interventions, there was no significant difference in body mass in any of dietary conditions (p >.05 ). After 3 hr swim exercise, blood lactate level was higher compared to resting conditions in all groups, but it was returned to resting value after 1 hr rest (p .05 ). Regardless of forms of glycogen, the highest level was observed in liver (p <.01 ), and most cases of supercompensation after 3hr exercise observed in this study were occurred in CHOW fed tissues. Except heart muscle, all tissues used in this study showed that pro- and macro-glycogen concentration was significantly decreased after 3 hr exercise. Based on these results, two conclusions were madefirst, there is no different level of glycogen content in various tissues regardless of types of fatty acids consumed and second, the highest mobilization rate would be demon-strated from CHOW fed animals compare to animals that consumed any kinds of fatty acid diet if prolonged exercise is applied.