中华倒刺鲃幼鱼能量代谢特征个体差异及生态关联

INDIVIDUAL VARIATION OF ENERGY METABOLISM CHARACTERISTICS AND ECOLOGICAL CORRELATION IN JUVENILE QINGBO (SPINIBARBUS SINENSIS)

  • 摘要: 为了探讨鱼类能量代谢特征个体变异及其生态关联, 以中华倒刺鲃(Spinibarbus sinensis)幼鱼为实验对象, 在25℃条件下测定44尾实验鱼的静止代谢率(Resting metabolic rate, RMR)、力竭运动后峰值代谢率(Peak metabolic rate, PMR)、力竭运动后过量耗氧(Excess post-exercise oxygen consumption, EPOC)、低氧胁迫后峰值代谢率PMR和低氧胁迫后过量耗氧(Excess post-hypoxia oxygen consumption, EPHOC)。研究发现, 中华倒刺鲃能量代谢特征参数存在较大个体差异, RMR、力竭运动后PMR、EPOC、低氧胁迫后PMR和EPHOC分别为193.62—460.33 mg O2/(kg·h)、617.9—2165.02 mg O2/(kg·h)、28.76—267.20 mg O2/kg、484.3—1142.97 mg O2/(kg·h)和30.27—211.88 mg O2/kg。力竭运动后PMR(r=0.348, P=0.010)和低氧胁迫后PMR(r=0.449, P=0.002)与RMR间均呈显著正相关; EPOC与RMR间呈显著负相关(r=–0.426, P=0.004), 而EPHOC与RMR间的关系不显著(r=–0.292, P=0.054); 力竭运动后PMR与EPOC间(r=0.424, P=0.004)和低氧胁迫后PMR与EPHOC间(r=0.391, P=0.009)均呈显著正相关。力竭运动后PMR与低氧胁迫后PMR(r=0.673, P<0.001)和EPOC与EPHOC(r=0.526, P<0.001)在个体差异均显著正相关; 然而力竭运动后PMR和EPOC分别显著高于低氧胁迫后PMR与EPHOC(P<0.05)。研究表明: 维持代谢较高的中华倒刺鲃个体有助于其快速提升有氧功率输出以维持高的游泳运动能力; 而较低维持代谢个体具有相对较高的EPHOC有助于机体在极端环境条件下提升其低氧耐受能力。中华倒刺鲃能量特征的个体变异可能是经长期自然选择适应环境的结果。

     

    Abstract: Metabolic energy fuels all biological processes, and thus, energy metabolism is vitally important for organisms. It has been suggested that individual variation in physiological functions is associated with the energetic metabolism of organisms, which varies considerably due to selection, adaptation and evolution. In order to explore the individual variation of energy metabolism characteristics of fish and its ecological correlation, we measured the resting metabolic rate (RMR), post-exercise peak metabolic rate (PMR), excess post-exercise oxygen consumption (EPOC), post-hypoxia PMR and excess post-hypoxia oxygen consumption (EPHOC) of 44 juveniles of qingbo individually at 25℃. We found that there are large inter-individual variations in the characteristic parameters of energy metabolism of qingbo. The RMR, post-exercise PMR, EPOC, post-hypoxia PMR and EPHOC were 193.62—460.33 mg O2/(kg·h), 617.9—2165.02 mg O2/(kg·h), 28.76—267.20 mg O2/kg, 484.3—1142.97 mg O2/(kg·h) and 30.27—211.88 mg O2/kg, respectively. The post-exercise PMR (r=0.348, P=0.010) and post-hypoxia PMR (r=0.449, P=0.002) were positively correlated with RMR. There was a significant negative correlation between EPOC and RMR (r=–0.426, P=0.004), whereas there was no significant relationship between EPHOC and RMR (r=–0.292, P=0.054). Furthermore, there were significant positive correlations between post-exercise PMR and EPOC (r=0.424, P=0.004), post-hypoxia PMR and EPHOC (r=0.391, P=0.009). Moreover, in terms of individual variation, the post-exercise PMR was consistent with post-hypoxia PMR (r=0.673, P<0.001), and EPOC also was consistent with EPHOC (r=0.526, P<0.001). However, post-exercise PMR and EPOC were significantly higher than either post-hypoxia PMR or EPOC (P<0.05). These results showed that the individual of qingbo with higher RMR might facilitate an improvement in the aerobic power output thus to maintain a high swimming ability, whereas the individual with lower RMR possess a relatively high EPHOC, which was helpful to improve the hypoxia tolerance under extreme environmental conditions. These results suggested the inter-individual variation of energy characteristics of qingbo was the result of natural selection during their long-term adaptation to the environment.

     

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