亚硝态氮对中华鳑鲏的急性毒性及短期影响

静水试验条件下研究了亚硝态氮对体质量(0.636±0.09) g的中华鳑鲏急性毒性及短期胁迫下对其体内两种酶活性的影响。在水温25℃、溶解氧6.3 mg/L、pH 7.4时,测定亚硝态氮对中华鳑鲏的24 h半致死质量浓度,并设置高、中、低3个亚硝态氮质量浓度组1.28、0.64、0.43 mg/L(1/10×24 h半致死质量浓度、1/20×24 h半致死质量浓度、1/30×24 h半致死质量浓度)],于0、24、48、72 h采集血样,测定血清中过氧化氢酶和碱性磷酸酶的活性。试验结果表明,亚硝态氮对中华鳑鲏的24 h半致死质量浓度为12.76 mg/L。在亚硝态氮胁迫作用下,中华鳑鲏血清中过氧化氢酶活性先显著上升,48 h后开始下降;碱性磷酸酶活性变化则是先显著下降,在48 h恢复,然后再下降。碱性磷酸酶活性在24 h和72 h均受到明显抑制。亚硝态氮质量浓度和暴露时间两者之间存在显著交互作用,碱性磷酸酶可以作为亚硝态氮毒性检测的生物标记物。

Acute Toxicity and Short-term Effects of Nitrite Nitrogen on Fish Rhodens sinensis

Both acute toxicity of nitrite nitrogen (6, 10, 11, 14, 16.6 mg/L and 18 mg/L) to fish Rhodens sinensis body weight (0.636±0.09) g]and short term effects of nitrite nitrogen on serum activities of catalase (CAT) and alkaline phosphatase (AKP) were investigated at pH 7.4, dissolved oxygen (DO) of 6.3 mg/L and 25 ℃ in a static test. The activities of CAT and AKP were determined in serum of the fishes exposed to 0.43 mg/L(1/30×24 h LC 50 ), 0.64 mg/L(1/20×24 h LC 50 ) and 1.28 mg/L(1/10×24 h LC 50 ) NaNO 2 concentrations at 0, 24, 48 h, and 72 h. The 24 h LC 50 of nitrite was showed to be 12.76 mg/L, and CAT activity was increased drastically at first and subsequently decreased after 48 h, while the activity of AKP decreased at 24 h, recovered at 48 h, and then decreased again. AKP activity was inhibited significantly at 24 h, and 72 h. There was significant interaction between nitrite concentration and exposure time, indicating that AKP could be used as a biochemical marker for nitrite stress.