Alsop D H, Kieffer J D, Wood C M
Centre for Fish Metabolism and Energetics, Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
Physiol Biochem Zool. 1999 Jul-Aug;72(4):474-83. doi: 10.1086/316686.
The effects of acclimation temperature (30 degrees, 20 degrees, and 15 degrees C) and swimming speed on the aerobic fuel use of the Nile tilapia (Oreochromis niloticus; 8-10 g, 8-9-cm fork length) were investigated using a respirometric approach. As acclimation temperature was decreased from 30 degrees C to 15 degrees C, resting oxygen consumption (Mo2) and carbon dioxide excretion (Mco2) decreased approximately twofold, while nitrogenous waste excretion (ammonia-N plus urea-N) decreased approximately fourfold. Instantaneous aerobic fuel usage was calculated from respiratory gas exchange. At 30 degrees C, resting Mo2 was fueled by 42% lipids, 27% carbohydrates, and 31% protein. At 15 degrees C, lipid use decreased to 21%, carbohydrate use increased greatly to 63%, and protein use decreased to 16%. These patterns at 30 degrees C and 15 degrees C in tilapia paralleled fuel use previously reported in rainbow trout acclimated to 15 degrees C and 5 degrees C, respectively. Temperature also had a pronounced effect on critical swimming speed (UCrit). Tilapia acclimated to 30 degrees C had a UCrit of 5.63+/-0. 06 body lengths/s (BL/s), while, at 20 degrees C, UCrit was significantly lower at 4.21+/-0.14 BL/s. Tilapia acclimated to 15 degrees C were unable or unwilling to swim. As tilapia swam at greater speeds, Mo2 increased exponentially; Mo2min and Mo2max were 5.8+/-0.6 and 21.2+/-1.5 micromol O2/g/h, respectively. Nitrogenous waste excretion increased to a lesser extent with swimming speed. At 30 degrees C, instantaneous protein use while swimming at 15 cm/s ( approximately 1.7 BL/s) was 23%, and at UCrit (5.6 BL/s), protein use dropped slightly to 17%. During a 48-h swim at 25 cm/s (2.7 BL/s, approximately 50% UCrit), Mo2 and urea excretion remained unchanged, while ammonia excretion more than doubled by 24 h and remained elevated 24 h later. These results revealed a shift to greater reliance on protein as an aerobic fuel during prolonged swimming.
采用呼吸测量法研究了驯化温度（30℃、20℃和15℃）和游泳速度对尼罗罗非鱼（Oreochromis niloticus；体重8 - 10克，叉长8 - 9厘米）有氧燃料利用的影响。随着驯化温度从30℃降至15℃，静息耗氧量（Mo2）和二氧化碳排出量（Mco2）大约下降了两倍，而含氮废物排出量（氨氮加尿素氮）大约下降了四倍。根据呼吸气体交换计算瞬时有氧燃料利用率。在30℃时，静息Mo2的燃料来源为42%的脂质、27%的碳水化合物和31%的蛋白质。在15℃时，脂质利用率降至21%，碳水化合物利用率大幅增至63%，蛋白质利用率降至16%。罗非鱼在30℃和15℃时的这些燃料利用模式分别与之前报道的适应15℃和5℃的虹鳟鱼的燃料利用情况相似。温度对临界游泳速度（UCrit）也有显著影响。适应30℃的罗非鱼的UCrit为5.63±0.06体长/秒（BL/s），而在20℃时，UCrit显著降低，为4.21±0.14 BL/s。适应15℃的罗非鱼无法或不愿意游泳。随着罗非鱼游泳速度加快，Mo2呈指数增加；Mo2min和Mo2max分别为5.8±0.6和21.2±1.5微摩尔O2/克/小时。含氮废物排出量随游泳速度增加的幅度较小。在30℃时，以15厘米/秒（约1.7 BL/s）游泳时的瞬时蛋白质利用率为23%，在UCrit（5.6 BL/s）时，蛋白质利用率略有下降至17%。在以25厘米/秒（2.7 BL/s，约50% UCrit）游泳48小时期间，Mo2和尿素排出量保持不变，而氨排出量在24小时内增加了一倍多，并在24小时后仍保持在较高水平。这些结果表明，在长时间游泳过程中，罗非鱼对蛋白质作为有氧燃料的依赖程度增加。
