Effect of Body Weight on Excess Post-Exercise Oxygen Consumpation in Mystus macropterus

The elevated oxygen consumption following exhaustive exercise, termed “excess post-exercise oxygen consumption” (EPOC) can be used to assess the non-aerobic oxygen cost of exercise. To investigate the relationship between body weight and non-aerobic oxygen capacity, the effect of body weight (<20g, 20-30g, 30-50g and >50g) on EPOC was study in largefin longbarbel catfish (Mystus macropterus ) at 25℃ using a open-flow respirometer. The results showed that resting oxygen consumption rates decreased significantly with the increase of body weight (p<0.05) and the values were 2.44, 2.25, 2.05 and 1.71 mgO2。min-1.kg-1 for <20g, 20-30g, 30-50g and >50g body weight groups, respectively. Time to peak oxygen consumption rate increased with body size, which were 1.31, 1.53, 1.89 and 4.50 min for <20g, 20-30g, 30-50g and >50g body weight groups, respectively. Peak oxygen consumption rates decreased significantly with the increase of body weight (p<0.05) and the values were 12.36, 11.07, 10.27 and 7.20 mgO2。min-1.kg-1 for <20g, 20-30g, 30-50g and >50g body weight groups, respectively, which were 5.36, 5.04, 5.23 and 4.22 that of resting oxygen consumption rate. The durations of post-exercise oxygen consumption to return to post-exercise stable level were 20, 20, 25 and 20 min. The excess post-exercise oxygen consumption above resting oxygen consumption during this period were 69.25, 64.89, 62.15 and 49.07 mg. This study suggested that the anaerobic metabolic capacity increased with the body weight in largefin longbarbel catfish.