Hot Water Extract of Leather Carp (Cyprinus carpio nudus) Improves Exercise Performance in Mice

The hot water extract of leather carp (Cyprinus carpio nudus) has been used as a nourishing tonic soup and as an aid for recovery from physical fatigue. In this study, we investigated the effect of leather carp extract on exercise performance in mice. Swimming endurance and forelimb grip strength were assessed following oral administration of the extract (once per day for 7 days) at a dose of $0.5 mg/10{\mu}L/g$ body weight. After 7 days, mice given the leather carp extract had significantly greater swimming endurance [$105{\pm}18s$ (P<0.05); 52% longer than day 0] and forelimb grip strength [$1.18{\pm}0.05$ Newton (P<0.01); 17% greater than day 0]. The extract increased muscle mass, but had little effect on body weight. Following the swimming exercise, blood glucose, glutathione peroxidase, and superoxide dismutase levels in extract-fed mice were significantly higher (145%, 131%, and 106%, respectively) than in the saline control group. Blood levels of high-density lipoprotein cholesterol were also significantly increased (128%) in mice given the extract compared to the controls. These results suggest that leather carp extract can improve physical exercise performance and prevent oxidative stress caused by exhaustive workouts.