秦岭细鳞鲑代谢及低氧耐受能力对温度驯化的响应

THE METABOLISM AND HYPOXIA TOLERANCE OF BRACHYMYSTAX LENOK TSINLINGENSIS IN RELATION TO TEMPERATURE ACCLIMATION

为考察秦岭细鳞鲑(Brachymystax lenok tsinlingensis)代谢及低氧耐受能力对温度驯化的响应,将实验鱼于6℃、12℃和18℃下驯化4周后,采用密闭式呼吸代谢测定仪对其静止代谢率(Resting metabolic rate,RMR)和临界氧压(Critical oxygen press,P_(crit))等参数进行测定。结果发现,RMR随驯化温度升高而升高,在6—12℃、12—18℃温度内,RMR的Q_(10)值分别为2.59和2.77,表明该物种对温度的敏感性较高;P_(crit)值随驯化温度升高而升高且与RMR显著正相关,在驯化温度范围内(6—18℃),P_(crit)提升了76.2%。研究结果提示:秦岭细鳞鲑应对低氧环境的生理可塑性较差,在高温下RMR增加可能是导致其低氧耐受能力降低的内在机制之一。

Brachymystax lenok tsinlingensis, a second-class state-protected wild animal in the China Red Data Book of Endangered Animals, is generally regarded as one of the southernmost-distributed Salmonidae fish. Although tempera-ture is critical for the survival and distribution of this species, information on its thermal physiology is extremely li-mited. In order to investigate the metabolism and hypoxia tolerance of B. lenok tsinlingensis in relation to temperature acclimation, fish were acclimated to the experimental temperature （6℃, 12℃, and 18℃） for 4 weeks, and sealed respirome-ters were used to determine the physiological parameters [e.g., resting metabolic rate （RMR） and critical oxygen press （Pcrit）]. Our results showed that the RMR increased with an increase in the acclimation temperature. The Q10 of RMR at 6—12℃and 12—18℃were 2.59 and 2.77, respectively, suggesting that B. lenok tsinlingensis was of high sensitivity to temperature changes. The Pcrit increased with an increase in the acclimation temperature, and the values of Pcrit in-creased by 76.2%over the acclimation temperature range （6—18℃）. Furthermore, significantly positive correlations were found between the Pcrit and the RMR. Our findings indicate that B. lenok tsinlingensis evolves poor physiological plasticity in response to hypoxic environment, and that increasing RMR at high temperatures may have contributed to the decreased hypoxia tolerance in B. lenok tsinlingensis.