温度对魁蚶能量代谢及抗氧化酶活性的影响

Effects of temperature on energy metabolism and antioxidant enzyme activities of Scapharca broughtonii

采用实验生态学方法,研究了魁蚶能量代谢及抗氧化酶活性对不同温度水平(20、23、26和29°C)的响应。结果显示,魁蚶的摄食率和排粪率都随着温度的升高而降低,单因素方差分析表明,温度显著影响魁蚶摄食率,而对排粪率的影响不显著。魁蚶耗氧率和排氨率随温度的升高呈先增高后降低的趋势,均显著受温度影响。通过建立能量收支方程,发现温度影响魁蚶的能量分配,20°C魁蚶呼吸能占13.71%、排泄能占1.89%、排粪能占22.94%、生长能占61.47%,但是超过20°C,摄食能显著减少,生长余力甚至出现负值。方差分析表明,温度对魁蚶的摄食能和生长余力均具有显著影响。魁蚶外套膜、鳃和肝胰腺的抗氧化酶活性分别在实验开始后的0、4、8、12、24、48和72 h取样检测,在20～29°C,魁蚶体内的T-AOC呈先升高后降低的趋势,且29°C温度下的T-AOC均低于其他温度组。短期内的高温刺激能够促使SOD和CAT活性升高,但超过24 h其组织中的SOD和CAT活性降低,其中鳃和肝胰腺的SOD和CAT活性受温度影响显著,而外套膜受温度影响不显著。GST活性在4～12 h内随着温度升高而显著升高,而在24 h后,尤其当温度升至29°C时,GST活性显著下降。本研究推测,高温对魁蚶的能量代谢及免疫能力造成严重的影响,导致机体抗氧化能力下降,这可能是夏季魁蚶死亡率较高的一个重要原因。研究表明,魁蚶的适宜温度狭窄,建议在魁蚶养殖生产中,水温应低于23°C,超过26°C会导致机体大量的能量消耗。

The energy metabolism and antioxidant enzyme activities of Scapharca broughtonii at different temperature levels(20,23,26 and 29℃)were studied in the laboratory.The results showed that the ingestion rate and the faecal egestion rate of S.broughtonii decreased with the increase of temperature.One-way ANOVA showed that temperature significantly affected the ingestion rate of S.broughtonii,but had no significant effect on the faecal egestion rate.The oxygen consumption rate and the ammonia excretion rate of S.broughtonii first increased and then decreased with the increase of temperature.Through the energy balance equation,we found that the temperature affected the energy allocation of S.broughtonii.Under the condition of 20℃,the energy of respiration was accounting for 13.71%,1.89%in excretion,22.94%in defecation,and 61.47%in growth.However,when the temperature was above 20℃,the ingested energy could be significantly decreased.Even negative growth occurred.The analysis of variance showed that the temperature had significant differences on the feeding capacity and growth capacity of S.broughtonii.The activities of antioxidant enzymes in the mantle membrane,gill and hepatopancreas of S.broughtonii were sampled and tested at 0,4,8,12,24,48 and 72 h after the treatments of temperature.In the range of 20–29℃,the activity of T-AOC first increased and then decreased,and it was significantly lower at 29℃than those at any other temperature groups.The results suggested that the short-term high-temperature stimulation promoted the activities of SOD and CAT,but decreased them beyond 24 h.The activities of SOD and CAT in gill and hepatopancreas were significantly affected by temperature,however,they were not significantly affected by temperature in mantle membrane.GST activity increased significantly with the increase of temperature within 4–12 h,but decreased significantly beyond 24 h,especially when the temperature rose to 29℃.Our studies have speculated that high temperature may lead to the reduction of antioxidant capacity in the organism,which has a serious impact on the energy metabolism and immune capacity of S.broughtonii.This may be an important reason for high death rate of S.broughtonii in summer.All the results suggest that the temperature for the actual production of S.broughtonii should be maintained below 23℃.It will generate a large amount of energy consumption of S.broughtonii if the temperature exceeds 26℃.