Casein hydrolysate supplementation enhances training effects on mitochondrial enzyme activities in slow muscle fibers but not in fast fibers in mice (706.18)

Aims: The aim of this study was to determine whether ingestion of casein hydrolysate enhances training effects on mitochondrial biogenesis. Methods: Mice were randomly divided into three treatment groups: the control group (CON), the endurance training group (Tr), and the endurance training with casein hydrolysate group (CH+Tr). Mice were ingested either water or casein hydrolysate (0.2 mg/g BW, 7 times/week) and subjected to endurance training (20‐25 m/min×60 min, 5 times/week, for 6 weeks) 30 min after the supplementation. Muscular mitochondrial enzyme activities, citrate synthase (CS) and β‐hydroxyacyl‐CoA dehydrogenase (β‐HAD) were measured. Results: In plantaris muscle, CS activities in Tr and CH+Tr groups were significantly higher than that in CON group (p<0.01) without significant differences between Tr group and CH+Tr group. On the other hand, CS activity in CH+Tr group was significantly higher than those in CON and Tr groups in soleus muscle (p<0.05). Similarly, in cardiac muscle, CS activity in CH+Tr group was significantly higher than that in Tr group (p<0.01) and tended to be higher comparing to CON group (p=0.051). β‐HAD activity was also increased in CH+Tr group in soleus and cardiac muscles. Conclusion: Casein hydrolysate supplementation enhances training effects on mitochondrial enzyme activities in slow muscle fibers but not in fast fibers. Grant Funding Source : Morinaga Milk Industry Co., Ltd