MEAL SIZE ON SWIMMING PERFORMANCE AND EXCESS POST-EXERCISE OXYGEN CONSUMPTION IN JUVENILE ANDRIAS DAVIDIANUS

Feeding and locomotion are two important physiological activities that occur simultaneously in life history of Andrias davidianus. Their exercise behavior varies according to different meal sizes, which is the result of long-term evolution and adaptation to different living environments. In order to investigate the effects of meal size on locomotion ability and energy metabolic of amphibians, we selected the juvenile Andrias davidianus as experimental subjects. We measured the induction velocity, burst swimming speed and excess post-exercise oxygen consumption (EPOC) at different meal sizes (0, 1%, 4%, and 10% of body weight). The induction velocity (20.78, 21.52, 23.67, 21.79 cm/s and 2.4, 2.49, 2.77, 2.56 bl/s, respectively) and burst swimming speed (32.65, 32.92, 35.42, 33.02 cm/s and 3.80, 3.81, 4.15, 3.85 bl/s, respectively) of juvenile A. davidianus were not significantly different among different meal sizes. With increasing meal size, the pre-exercise metabolic rate 66.88, 82.51, 95.57 and 106.32 mg O₂/(kg·h), respectively and the peak post-exercise metabolic rate 148.21, 155.08, 166.93 and 167.63 mg O₂/(kg·h), respectively increased gradually and were significantly higher in the 4% and 10% meal size groups than those in the control group (P<0.05). The increment of metabolic rate 81.33, 72.57, 71.36 and 61.31 mg O₂/(kg·h), respectively, factorial scope (2.26, 1.89, 1.76 and 1.58, respectively), duration (55.00min, 49.60min, 38.80min, 32.10min, respectively) and EPOC magnitude (27.48, 23.68, 21.42 and 15.36 mg O₂/kg, respectively) declined progressively, and these indexes in 4% and 10% meal size groups were lower than that in the control group (P<0.05). Our results suggested that the swimming performance of juvenile A. davidianus is not affected by feeding. These movement characteristics of this species should be fully considered in the practice of habitat protection and release in wild. The maintenance of swimming ability, the increase of aerobic metabolism and the shortening of recovery time after feeding may be beneficial for juvenile A. davidianus to hunt and escape from predators, resulting in better adaptation to the complex stream habitat and improved survival fitness.