温度对鳊幼鱼临界游泳速度和代谢范围的影响

Effects of water temperature on the critical swimming speed and metabolic scope of juvenile Parabramis pekinensis

为了考查温度对鳊(Parabramis pekinensis)幼鱼有氧运动能力的影响并探讨有关代谢机制,本研究分别在不同温度(10、18、26和34℃)下测定实验鱼的静止耗氧率(RMR)、临界游泳速度(Ucrit)和运动过程中的最大耗氧率(MMR),并以MMR和RMR的差值分别计算各温度下的能量代谢范围(MS)。结果表明:随着温度的上升,Ucrit呈现显著上升的趋势(P<0.05),温度由10℃升高至34℃,Ucrit由(6.01±0.32)升至(8.82±0.27)BL·s-1;RMR和MMR也随温度的升高呈现显著上升趋势(P<0.05),其测定值在温度由10℃升高至34℃时分别为(161.7±28.8)、(293.0±27.6)mgO2·kg-1·h-1和(558.6±20.4)、(1278.7±57.4)mgO2·kg-1·h-1,MMR在34℃与26℃相比有下降趋势;MS在10～26℃范围随温度的上升显著上升,26～34℃却出现显著下降(P<0.05)。可见:Ucrit和MS在高温条件下的反应不尽一致;这可能与水的粘滞系数下降、进而导致鳊能量效率提升有关,还可能由于实验鱼无氧代谢能力提高所致。

In order to understand the effects of water temperature on the aerobic locomotor capac- ity and its relationships with the energetic metabolism of juvenile Parabramis pekinensis, the ju- veniles were put into the waters at different temperature （10, 18, 26, and 34 ℃ ） to measure their resting metabolic rate （RMR）, critical swimming speed （Uont）, and maximal metabolic rate （MMR） during swimming, and the differences of MMR-RMR at different water temperature were used to calculate the metabolic scope （MS） of the juveniles. Both the Ucnt and the RMR in- creased significantly with increasing water temperature （P〈0.05）. The Ucrtt was increased from 6.01±0.32 BL · s-1 to 8.82±0.27 BL· s^-1 when the water temperature increased from 10 to 34℃, and the MMR increased significantly when the temperature increased from 10 and 26 ℃, and remained unchanged with the further increase of temperature. The RMR and MMR were 161.7 ±28.81 mg O2 · kg^-1· h-1 and 292.95 ±27.59 mg O2 · kg^-1· h-1at 10 ℃, and 558.55±20.41 mg O2 · kg^-1· h-1 and 1278.74± 57.40 O2 · kg^-1· h-1at 34 ℃, respec- tively. The MS increased significantly when the temperature increased from 10 to 26 ℃ （P〈 0. 05）, but decreased significantly when the temperature further increased from 26 to 34 ℃. It was suggested that the different reaction patterns of the MS and Ucrit, to the changes of water tem- perature were possibly due to the high swimming efficiency as the results of the decreased water viscosity coefficient and the high anaerobic metabolism capacity of the fish at high water tempera- ture.