Effect of exercise training on respiration and reactive oxygen species metabolism in eel red muscle

This paper deals with the effects of exercise training on oxygen consumption (MO2) and ROS metabolism in the red muscle of trained and untrained female silver eels. Their critical swimming speed (Ucrit) was determined before and after a 4-day training (10 h of swimming at 70% of Ucrit and 14 h at 50%, every day). The Ucrit of trained eels increased significantly (by about 7%). The in vitro MO2 and ROS production by the red fibres were higher (not significant) in trained than in untrained eels, but the ROS production/MO2 ratio was alike in both groups. The antioxidant-enzyme activities and lipoperoxidation index in trained eels were both lower than those of the untrained ones. These biochemical changes related to the increase in Ucrit suggest that such a training session could maintained or even increased aerobic power of the red muscle without deleterious impact by ROS. These regulations could play a role in the eel's swimming performance efficiency.