高温胁迫对厚壳贻贝摄食、代谢和相关酶活性的影响

Effects of heat stress on feeding,metabolism and related enzyme activities of Mytilus coruscus

为了探讨高温胁迫对厚壳贻贝生理代谢和免疫功能的影响,测定了不同温度胁迫水平(20→25℃;20→30℃)下厚壳贻贝的滤水率、耗氧率、排氨率以及不同组织己糖激酶(HK)、丙酮酸激酶(PK)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)和超氧化物歧化酶(SOD)的活性。结果表明:25℃胁迫3 h后厚壳贻贝滤水率升高至0.56 L·g^-1·h^-1,但与对照组相比无显著变化,30℃处理后滤水率则显著降低;高温胁迫处理后,厚壳贻贝的耗氧率与排氨率均显著升高,25℃与30℃处理组间耗氧率无显著差异,但30℃处理组排氨率显著低于25℃;与对照组相比,外套膜和鳃HK活性无显著变化,但肝胰腺HK活性显著降低,鳃部HK活性显著高于外套膜和肝胰腺;外套膜PK活性显著升高,在30℃达到最大值,而25℃胁迫处理组鳃PK活性却显著降低;高温胁迫后外套膜ACP活性显著降低,25℃处理组肝胰腺ACP活性显著降低,但各处理组间鳃ACP活性无显著差异;25℃下外套膜AKP活性显著升高,30℃时鳃和肝胰腺AKP活性显著低于对照组;30℃胁迫下外套膜SOD活性显著升高,鳃和肝胰腺SOD活性无显著变化,肝胰腺SOD活性显著低于鳃和外套膜。实验表明,一定温度变化范围内,厚壳贻贝可通过调节自身代谢水平应对温度升高带来的胁迫,但短时间内大幅升温显著影响厚壳贻贝的摄食、代谢和免疫反应。厚壳贻贝代谢酶和免疫酶活性具有组织特异性。

To clarify the effects of heat stress on the physiological metabolism and immune functions of Mytilus coruscus,we measured the clearance rate,oxygen consumption rate,ammonia excretion rate,hexokinase(HK),pyruvate kinase(PK),acid phosphatase(ACP),alkaline phosphatase(AKP),and superoxide dismutase(SOD)activities in different tissues of M.coruscus under different stress levels(from 20℃to 25℃and from 20℃to 30℃).The results showed that the clearance rate increased to 0.56 L·g^-1·h^-1 at 25℃for 3 h,but was not significantly different from the control group.The clearance rate was significantly reduced after 30℃.The mussel’s oxygen consumption rate and ammonia excretion rate were significantly increased when subjected to heat stress.Oxygen consumption rate was not different between 25 and 30℃treatment,but the ammonia excretion rate was significantly lower at 30℃than at 25℃.Compared with the control group,HK activity did not change in mantle and gill,but the HK activity in hepatopancreas was significantly decreased.HK activity was significantly higher in gill than in mantle and hepatopancreas.The PK activity was significantly increased after high temperature treatment,and peaked at 30℃,in contrast to a significant decrease of PK activity in gill at 30℃.A significant decrease in ACP activity in mantle was observed.The ACP activity in hepatopancreas was significantly decreased at 25℃,but ACP activity in gill did not change.The mantle’s AKP activity increased significantly at 25℃.In contrast,the gill’s and digestive gland’s AKP activity was significantly lowered at 30℃.The mantle’s SOD activity increased significantly at 30℃.SOD activity did not differ between gill and hepatopancreas.The hepatopancreas’s SOD activity was significantly lower than those in gill and mantle.Our results indicated that M.coruscus can adjust its metabolism level to cope with the heat stress under a certain range of temperature.Acute temperature increase could significantly affect its feeding,metabolism and immune function.The activities of M.coruscus’metabolic and immune-related enzymes are tissue-specific.