温度对三疣梭子蟹呼吸代谢及其相关酶活力的影响

Effects of temperature on the respiratory metabolism and activities of related enzymes of swimming crab Portunus trituberculatus

关键词:  三疣梭子蟹  温度  耗氧率  排氨率  氧氮比  呼吸代谢酶

Key words:  Portunus trituberculatus  Temperature  Oxygen consumption rate  Ammonia excretion rate  O/N ratio  Energy metabolism enzyme activities

摘要:

为研究温度对三疣梭子蟹Portunus trituberculatus呼吸代谢的影响，以三疣梭子蟹幼蟹（1.17±0.03）g和成蟹（57.57±1.16）g为实验材料，设5个实验温度水平（15、18、21、24、27℃），测定其在不同温度下的耗氧率和排氨率以及成蟹肝胰脏和肌肉组织中的丙酮酸激酶( PK)、己糖激酶( HK)和琥珀酸脱氢酶( SDH)的活力。实验结果显示，三疣梭子蟹耗氧率和排氨率均随温度的升高而升高。幼蟹耗氧率在各个温度水平下差异显著（P<0.05），成蟹耗氧率仅在15-18℃与21-27℃之间差异显著（P<0.05）；幼蟹和成蟹排氨率在15-18℃与21-27℃之间差异显著（P<0.05）。幼蟹和成蟹的氧氮比随温度的升高总体呈下降趋势，其氧氮比范围为1.38-3.02，表明三疣梭子蟹以蛋白质为主要代谢能源物质。随实验温度升高，成蟹肝胰脏中的PK活力呈上升趋势，而成蟹肌肉组织中的PK和HK的活力则随温度升高总体呈下降趋势。温度对三疣梭子蟹肝胰脏组织中SDH的活力影响显著（P<0.05），SDH的活力随温度的升高呈上升趋势，在27℃时达到最大值。综上所述，无氧代谢方面，随实验温度的升高，三疣梭子蟹成蟹肝胰脏组织的糖酵解速率增大，肌肉组织对葡萄糖的利用能力下降；有氧代谢方面，成蟹肝胰脏SDH活力随实验温度的升高而升高，一定程度上反应了三疣梭子蟹在高温环境下有氧代谢加强。

Abstract:

An experiment was carried out to investigate the effects of temperature on the respiratory metabolism of swimming crab Portunus trituberculatus. Oxygen consumption rate, ammonia excretion rate of juvenile（1.17±0.03g）and adult (57.57±1.16g) crabs and activity of energy metabolism enzymes, pyruvate kinase(PK)，hexokinase(HK) and succinate dehydrogenase (SDH) in muscle and liver of adult crab， were measured at 15℃,18℃,21℃,24℃and 27℃. The results were as follows:with the increase of temperature, both oxygen consumption rate and ammonia excretion rate increased significantly（P<0.05）. Oxygen consumption rate of juvenile crab at various temperatures and adult carb at 15-18℃ and 21-27℃ had significant difference （P<0.05）. Ammonia excretion rate of both juvenile and adult crabs had significant difference at 15-18℃ and 21-27℃（P<0.05）.The ratio of oxygen to nitrogen (1.38-3.02)demonstrated that the metabolic substrates of crab P.trituberculatus was protein-dominant and it displayed a decreasing trend as the temperature increased. Activity of PK in liver had an upward trend as temperature increased. However, activities of PK and HK in muscle displayed a decreasing trend（P<0.05）. Activity of SDH in liver increased as temperature increased （P<0.05）and reached the highest level at 27℃. In summary,the rate of glycolysis increased in the liver of swimming crab， and a gradual decreasing glucose-utilizing capability in muscle was observed. Activity of SDH in liver was enhanced as temperature increased （P<0.05）, which indicated a strengthed aerobic metabolism of swimming crab at high temperature.