盐度与体重对克氏原螯虾代谢的影响

Effects of salinity and body weight on metabolism of Procambarus clarkii

在水温为20．0±0．5℃条件下，研究了不同盐度（0、3．0、6．0、9．0、12．0）和不同体重（平均体重为7～8g、19—20g两种规格）对克氏原螯虾的耗氧率、CO2排出率以及NH3-N排泄率的影响。结果表明，低盐度条件下（0～6．0），两种规格克氏原螯虾的耗氧率、CO2排出率和NH3-N排泄率均随着盐度的升高而显著上升（P〈0．05），盐度为6的条件下代谢水平达最高值，此后随着盐度的升高耗氧率、CO2排出率和NH3-N排泄率显著下降（P〈0．05）；相同盐度下，小规格（平均体重为7～8g）克氏原螯虾的耗氧率、CO2和NH3-N排泄率显著高于大规格虾（平均体重为19～20g）。相同规格的克氏原螯虾在不同盐度条件下呼吸商、氧氮比均无显著差异（P〉0．05），但是大规格的克氏原螯虾呼吸商和氧氮比显著大于小规格的虾（P〈0．05），前者的代谢率极显著低于后者（P〈0．01）。

The study was performed to investigate the effects of salinity and body weight on oxygen consumption, CO2 production and ammonia-N excretion of swamp crayfish Procambarus clarkii under the water temperature of 20.0 ± 0.5 ℃. The crayfish were divided into two groups by their average body weight of 7 - 8 g and 19 ～ 20 g and five salinity groups ranged from 0 to 12.0 with the interval of 3. The results showed that the oxygen consumption, CO2 production and ammonia-N excretion of the two groups of Procambarus clarkii increased significantly with the increment of salinity at low salinity levels （ 0 ～ 6） （ P 〈 0.05 ）, the highest level of metabolism was found in the group of salinity of 6. Then the oxygen consumption, CO2 production and ammonia-N excretion of Procambarus clarkii decreased apparently with the increment of salinity in the range of 6.0 -12.0（P 〈 0.05 ）. At the same salinity level, the oxygen consumption, CO2 production and ammonia-N excretion of Procambarus clarkii of the small size （ average body weight of 7 - 8 g） were significantly higher than those of the large size （ average body weight of 19 - 20 g）. No great differences were found on the respiratory quotient and oxygen-nitrogen ratio of Procambarus clarkii in the same weight level of all salinity groups （P 〉 0.05 ）. However, the respiratory quotient and oxygen-nitrogen ratio of Procambarus clarkii of the large size were significantly higher than those of the small size （P 〈 0.05 ）, whilst the metabolism ratio of the former was considerablely lower than that of the latter （P 〈 0.01 ）.