Effects Of Acceleration Modes On Metabolic Recovery Of Silurus Meridionalis And Megalobrama Amblycephala After Exhaustive Swimming

To investigate the effects of acceleration modes on parameters of metabolic recovery for the fishes with different ecological habits,four acceleration modes composed of different acceleration duration??t?and velocity increment??v?were set up to estimate excess post-exercise oxygen consumption?EPOC?of S.meridionalis and M.amblycephala after exhaustion caused by burst swimming(U_burst group,?v=20 cm/s,?t=2 min)or sustained swimming(U_crit groups,?v=10 cm/s,?t=20,40 and60 min)by a recirculating swimming flume.The water temperature was 25±0.5?.The main results were as follows:1.The peak of EPOC after burst swimming was significantly higher than that in each of the three U_crit groups for S.meridionalis?P<0.05?.There was no significant difference for the peaks of EPOC among all acceleration modes for M.amblycephala.2.In the process of metabolic recovery,oxygen consumption rate?MO₂?decreased sharply in 20 minutes after exhaustion,and then decreased slowly with the recovery time until it returns to the pre-exercise level.3.The oxygen consumption in the first 20 minutes after exhaustion in U_burst group for S.meridionalis was significantly higher than that in each of the three U_crit groups?P<0.05?.But there was no such difference for M.amblycephala.4.The magnitude of EPOC in the U_burst group for S.meridionalis was significantly higher than that in each of three U_crit groups?P<0.05?,and there was no significant difference in the magnitude of EPOC among the four acceleration modes for M.amblycephala.5.The magnitude of EPOC in the U_burst group for S.meridionalis was 286.6%,359.5%,and 816.5%higher respectively than those in its three U_crit groups,while the values for M.amblycephala were 20.6%,14.8%,and 29.0%,respectively.6.The duration of EPOC in the U_burst group for S.meridionalis was significantly higher than that in each of the other three groups?P<0.05?.However,there was no significant difference among the four groups with different acceleration modes for the durations of EPOC of M.amblycephala.Each duration of EPOC of S.meridionalis in four groups was shorter than that of M.amblycephala under the same acceleration mode.7.The proportion of anaerobic metabolism in the U_burst group for S.meridionalis and M.amblycephala were 0.72 and 0.64,which were significantly higher than that in each of three U_crit groups respectively?P<0.05?.The proportion of anaerobic metabolism of the two species in the three U_crit groups ranged from 0.04 to 0.12,which decreased with the increase of the acceleration duration.However,there was no significant difference for these values between S.meridionalis and M.amblycephala under the same accelerated mode.The main conclusions were as follows:1.The process of metabolic recovery for S.meridionalis and M.amblycephala after exhaustion caused by burst swimming or sustained swimming could be divided into two phases:a rapid recovery phase and a slow recovery phase.2.S.meridionalis has a higher dependence on anaerobic metabolism during swimming.The ability of anaerobic metabolism for this species is stronger during burst swimming,which can greatly improve the swimming speed.And it can take less time for metabolic recovery after exhaustive swimming.3.The swimming process of M.amblycephala mainly depend on aerobic metabolism,which can maintain high speed swimming for a long time.But the duration of metabolic recovery after exhaustive swimming is longer.4.Differences in swimming performance and mechanism of activity metabolism between the two species might reflect the trade-off effect in adapting to their ecological habits.