氨氮和亚硝酸盐氮对美洲鲥幼鱼的急性胁迫研究

Ammonia and Nitrite Acute Stress Test on the Alosa Sapidissima Larvae

采用水生生物毒性试验方法,开展了氨氮和亚硝酸盐氮对美洲鲥幼鱼的急性胁迫试验。采集美洲鲥幼鱼不同胁迫时间下的肝脏组织,测定其超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GPX)活性。结果表明,美洲鲥幼鱼在氨氮和亚硝酸盐氮胁迫24,48,72和96 h时,半致死浓度分别为70.20,53.00,46.80和46.50 mg/L和776.80,679.40,568.50和537.70 mg/L,安全浓度分别为4.65和53.80 mg/L。氨氮和亚硝酸盐氮胁迫下的SOD、CAT和GPX活性,均随时间的增加呈降低趋势,并在96 h时活性达到最低值。在氨氮胁迫下,SOD活性整体呈下降趋势,CAT和GPX活性在96 h时显著下降(P<0.05)。在亚硝酸盐氮胁迫下,SOD、CAT和GPX活性整体趋势与氨氮胁迫下相似,氨氮和亚硝酸盐氮在各个时间点,SOD、CAT和GPX差异均不显著(P>0.05)。

Conducted acute stress tests on Alosa sapidissima larvae with ammonia nitrogen and nitrite nitrogen.According to the aquatic biotoxicity testing method,liver tissues of Alosa sapidissima larvae under different stress times were collected to measure the activities of superoxide dismutase(SOD),catalase(CAT),and glutathione peroxidase(GPX).The results indicate that the median lethal concentrations(LC50)of ammonia nitrogen and nitrite nitrogen for Alosa sapidissima larvae at 24,48,72,and 96 hours of stress were 70.20,53.00,46.80,46.50 mg/L and 776.80,679.40,568.50,537.70 mg/L,respectively.The safe concentrations were found to be 4.65 mg/L and 53.80 mg/L.Under ammonia nitrogen and nitrite nitrogen stress,the activities of SOD,CAT,and GPX decreased with increasing time,reaching the lowest values at 96 hours.Under ammonia nitrogen stress,SOD activity showed an overall decreasing trend,while CAT and GPX activities significantly decreased at 96 hours(P<0.05).Under nitrite nitrogen stress,the overall trends of SOD,CAT,and GPX activities were similar to those under ammonia nitrogen stress,and there was no significant difference between them at all time points(P>0.05).