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

Lee, Jongsam; Kim, Jaechul; Kwon, Youngwoo; Lee, Jangkyu; Lee, Jeongpil; Yoon, Chungsoo

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 groups :animals 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 subgroups :sacrificed 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 ). Free fatty acid concentration was higher in all high fat fed groups (regardless of fatty acid composition )than CHOW consumed group. At rest, pro- & macro-glycogen concentration was not different from any of experimental groups (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 made :first, 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.