Abstract
The effects of dietary supplementation of Eleutherococcus senticosus, taurine and carnitine on maximal endurance exercise performance along with other related parameters were evaluated in rats that underwent aerobic exercise training for 6 weeks. Thirty-two male rats (4 weeks old) were randomly divided into 4 groups, and fed experimental diets and/or aerobic exercise trained according to the protocol: SC (sedentary control group), EC (exercise-trained control group), EE (exercise-trained Eleutherococcus senticosus-supplemented group), and EETC (exercise-trained Eleutherococcus senticosus, taurine and carnitine-supplemented group). The food efficiency ratio of EC rats was significantly lower than the value for SC rats (p < 0.01). Exercise-trained control animals (92 $\pm$ 8.8 min) could run significantly longer until exhausted on the treadmill than sedentary control rats (11 $\pm$ 0.8 min) (p < 0.001). Animals fed an Eleutherococcus senticosus-supplemented diet, and an Eleuthherococcus sonticosus, taurine and carnitine- supplemented diet while undergoing aerobic exercise training for 6 weeks exhibited, respectively, 8 and 5 minutes longer running performance until exhausted than the rats fed the control diet. The gastrocnemius muscle glycogen concentration of the rats, measured at 48 hours post maximal exercise performance test, was 43% higher in EC rats than the value for SC rats (p < 0.05), but was not different among EC, EE, and EETC rats. The mitochondrial citrate synthase activity of the soleus muscle was significantly higher in EC rats compared to the value for SC rats (p < 0.01), and showed a tendency to increase, without statistical significance, in EE or EETC rats compared to the value for EC rats. These results indicate that aerobic exercise training for 6 weeks significantly improved maximal exercise performance, muscle glycogen content along with citrate synthase activity, which are important in the energy metabolism of muscle under aerobic exercise. Dietary supplementation of Eleutherococcus senticosus in rats while undergoing aerobic exercise training improved maximal endurance exercise performance without significantly affecting muscle glycogen content and enzyme activities involved in energy metabolism during exercise. Taurine and carnitine supplementation failed to show an additive effect on maximal endurance exercise performance when consumed along with Eleutherococcus senticosus.