摘要:为了探讨体重对中华倒刺鲃能量代谢和热耐受特征的影响，在25℃条件下分别测定不同体重大小（1、10、25、 > 50 g组）中华倒刺鲃的静止代谢率（Resting metabolic rate，RMR）、力竭运动后过量耗氧（Excess post-exercise oxygen consumption，EPOC）和热耐受参数。随体重的增加，中华倒刺鲃个体RMR、最大代谢率（Maximum metabolic rate，MMR）、代谢空间（Metabolic scope，MS）和EPOC均显著增加（P < 0.05）；单位体重RMR、MMR和MS则均显著降低，而单位体重EPOC随体重的增加显著增加（P < 0.05）。RMR、MMR、MS和EPOC的代谢尺度指数分别为0.796、0.834、0.849和1.137且显著大于2/3，因此中华倒刺鲃的能量代谢参数均呈异速度增加的关系而变化。这些变化可能与其个体变大游泳运动能力增强导致能量代谢需求增加相关。中华倒刺鲃临界低温（Critical thermal minimum，CT_min）和致死低温（Lethal thermal minimum，IL_min）与体重之间均呈"微笑型"二次函数的关系，临界高温（Critical thermal maximum，CT_max）和致死高温（Lethal thermal maximum，IL_max）均呈"钟型"二次函数的关系，因此中等大小的中华倒刺鲃具有更强的热耐受能力。这种非线性关系可能与其生长发育阶段和温度驯化历时有关。



Abstract:The physiological performance of animals can be affected by many factors, of which the body mass is an important one. In order to investigate effects of body mass on energy metabolism and thermal tolerance in Qingbo (Spinibarbus sinensis), we firstly measured the resting metabolic rate (RMR), maximum metabolic rate (MMR), metabolic scope (MS, MMR-RMR), and excess post-exercise oxygen consumption (EPOC) of fish with different body mass (1, 10, 25, and > 50g groups) at 25℃. Then the critical thermal minimum (CT_min), lethal thermal minimum (LT_min), critical thermal maximum (CT_max), and lethal thermal maximum (LT_max) of fish were measured. The RMR, MMR, MS, and EPOC increased significantly with body mass of Qingbo (P < 0.05). The relationship between ln[RMR (mg h^-1 fish^-1)] and ln[body mass (g)] was described as y=0.796x-1.123 (R²=0.983, n=32, P < 0.001), while y=0.834x-0.322 (R²=0.985, n=32, P < 0.001), y=0.849x-0.030 (R²=0.972, n=32, P < 0.001), and y=1.137x-2.099 (R²=0.943, n=32, P < 0.001) were adopted to illustrate the relationships between metabolic parameters including ln[MMR (mg h^-1 fish^-1)], ln[MS (mg h^-1 fish^-1)], ln[EPOC (mg fish^-1)], and ln[body mass (g)], respectively. These relationships indicated that all parameters of metabolic traits were following allometry models with body mass, and these scaling exponents for metabolic traits (i.e., the slope of equation) were significantly greater than 2/3 (P < 0.05). Moreover, the RMR, MMR, and MS of unit body mass Qingbo significantly decreased (P < 0.05), however, that of EPOC distinctly increased with body mass (P < 0.05). The results may be related to the increased metabolic demands of swimming with the increase of body mass. The relationships between CT_min and CT_max (℃) and body mass (g) were described as y_CTmin=0.0007x²+0.0459x+9.191 (R²=0.685, n=16, P_quadric < 0.001) and y_CTmax=-0.0003x²+0.0202x+39.198 (R²=0.293, n=16, P_quadric=0.083), respectively. While those between LT_min and LT_max (℃) and body mass (g) were described as y_LTmin=0.0003x²+0.0351x+6.581 (R²=0.657, n=16, P_quadric=0.005) and y_LTmax=-0.0003x²+0.0204x+40.285 (R²=0.392, n=16, P_quadric=0.041), respectively. These relationships indicated that the thermal tolerance of the intermediate body mass Qingbo was the strongest, which was possibly related to the variant developmental stages and temperature acclimation period in the experimental fish.





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