不同游泳速度条件下瓦氏黄颡幼鱼的有氧和无氧代谢反应

在(25±1)℃的条件下,测定瓦氏黄颡(Pelteobagrus vachelli Richardson)幼鱼体重(4.34±0.13)g的临界游泳速度(Ucrit),然后分别以临界游泳速度的不同百分比(20、40、60、80、100%Ucrit)将实验鱼分为5个速度处理组,另外设置静止对照组和高速力竭对照组。处理组实验鱼在不同游泳速度下分别游泳20min,在此过程中测定并计算运动代谢率(Activity metabolic rate,AMR),随后测定肌肉、血液和肝脏中的乳酸、糖原和葡萄糖含量。结果显示:实验鱼的绝对临界游泳速度为(48.28±1.02)cm/s,相对临界游泳速度为(6.78±0.16)BL/s;随着游泳速度的提高AMR显著增加(Pcrit时肌乳酸和血乳酸含量显著高于80%Ucrit的水平(P0.05);100%Ucrit时肝糖原含量显著低于40%Ucrit的水平(P0.05)。经计算瓦氏黄颡幼鱼到达临界游泳速度时的无氧代谢功率比例仅为11.0%,表明其游泳运动主要以有氧代谢供能;实验鱼的无氧代谢大约在80%Ucrit才开始启动,与其他鱼类比较启动时间较晚,说明其游泳运动对无氧代谢的依赖程度较低。研究提示瓦氏黄颡幼鱼是一种有氧运动能力较强的鱼类,这一能量代谢特征可能与提高其生存适合度有关。  

AEROBIC AND ANAEROBIC METABOLISM IN RESPONSE TO DIFFERENT SWIMMING SPEED OF JUVENILE DARKBARBEL CATFISH(PELTEOBAGRUS VACHELLI RICHARDSON)

The aim of this study were, to determine the anaerobic to aerobic metabolism ratio under the maximum sus-tainable swimming speed (critical swimming speed, Ucrit) of selected fish species, to examine at what swimming speed fish start to recruit its anaerobic metabolism, and hence to investigate the relationship among locomotion performance, energy supply characteristics and ecological habits of selected experimental animal. Juvenile darkbarbel catfish (Pelteobagrus vachelli Richardson) w: (4.34±0.13) g, an economic fish species distribute widely in the Yangtze River and Pearl River, were chosen as the experimental animal. The critical swimming speed (Ucrit) of juvenile Darkbarbel Catfish was determined at (25 ± 1)℃. Based on the Ucrit data, we set 7 experimental groups: 2 control groups (resting control group and high-speed exhaustive control group) and 5 speed-manipulating groups, which were set following the gradient of mean Ucrit (20, 40, 60, 80 and 100% Ucrit). Fish of speed-manipulating groups were forced to swim for 20 minutes at its setting speed, during this period, the oxygen consumption rate was measured and the activity metabolic rate was calculated. The lactate, glycogen and glucose levels of muscle, blood and liver of fish in experimental treatment groups were determined immediately after forced swimming. The biochemical parameters and resting metabolic rate (only for resting control group) were also measured in two control groups. The absolutely critical swimming speed of juvenile darkbarbel catfish in this study was (48.28±1.02) cm/s and the relative critical swimming speed was (6.78±0.16) BL/s. The oxygen consumption rate raised significantly with the increasing of the swimming speed (P 0.05). The mus-cle and blood lactate levels of fish underwent 100% Ucrit treatment were (7.25±0.70) μmol/g and (9.25±2.66) mmol/L while the lactate levles of muscle and blood samples were (5.31±0.43) μmol/g and (3.44±0.25) mmol/L, respectively. The lactate levels of both muscle and blood samples of 100% Ucrit treatment group were significantly higher than those of 80% Ucrit treatment group (P 0.05) while the lactate level of liver showed no significant change (P 0.05); As swimming speed increased, glycogen content of all three tissues showed a downward trend (P 0.05), of which liver glycogen content of 100% Ucrit group was significantly lower than that of 40% Ucrit level (P 0.05) while glycogen content of muscle showed no significant difference among all experimental treatment groups (P 0.05). Glucose levels remained relatively stable. Calculated anaerobic metabolism to aerobic metabolism power ratio was 11.0% when juve-nile Darkbarbel Catfish reached the critical swimming speed, indicating that the main power came from aerobic me-tabolism path; anaerobic metabolism started its function when fish reached around 80% of its Ucrit, the start-up time was late comparing with other fish. It showed that their swimming activity relied less on anaerobic metabolism. This study indicates that juvenile Darkbarbel Catfish has strong aerobic capacity and the characteristics of energy metabolism in this fish species may be related to its higher survival fitness.