氨氮对拟穴青蟹的急性毒性及对其血清免疫相关酶活力的影响

采用静水法研究氨氮对拟穴青蟹(Scylla paramamosain)的急性毒性及在氨氮初始浓度分别为0(C0,对照组)、10(C10组)、20(C20组)、30(C30组)、40(C40组)、50 mg/L(C50组),胁迫时间分别为0、6、24、48、72 h的条件下对其血清中碱性磷酸酶(AKP)、酸性磷酸酶(ACP)、溶菌酶(LZM)、超氧化物歧化酶(SOD)和酚氧化酶(PO)活力的影响。结果显示,总氨氮对拟穴青蟹24 h和48 h的半致死浓度分别为104.793、66.124 mg/L,安全浓度为7.90 mg/L,非离子氨对拟穴青蟹24 h和48 h的半致死浓度分别为8.396、5.298 mg/L,安全浓度为0.63 mg/L。在胁迫6、24、48与72 h时,各实验组的LZM活力均显著低于对照组(P0.01)。相较于对照组,C10、C20及C40组在24 h的AKP、ACP活力均显著升高(P0.05)。C20组在24 h的SOD活力则显著低于其他胁迫时间点(P0.05)。胁迫72 h时,C30、C40及C50组的PO活力显著高于对照组(P0.05)。该实验条件下,不高于40 mg/L的氨氮可在24 h内使拟穴青蟹血清中的AKP与ACP活力显著升高,而50 mg/L的氨氮则对其具有抑制作用;各实验组浓度氨氮均在72 h内对拟穴青蟹血清中的LZM活力具有显著的抑制作用,对PO活力具有明显的刺激作用,对SOD活力无显著影响。

Acute Toxicity of Ammonia Nitrogen to Scylla paramamosain and Its Influence on Immune Factors in Serum

Using the toxicity method, we studied the acute toxicity of ammonia nitrogen to Scylla paramamosain and its influence on phenol oxidase (PO), alkaline phosphatase (AKP), acid phosphatase (ACP), superoxide dismutase (SOD) , and lysozyme (LZM) in the conditions of different ammonia nitrogen concentrations of 0 (C0, control group), 10 (C10), 20 (C20), 30 (C30), 40 (C40), 50 mg/L (C50) and different times of 0, 6, 24, 48, and 72 h. The results showed that the semi-lethal concentration (LC50) at 24 and 48 h of ammonia-N were 104.793 and 66.124 mg/L respectively, and the safe concentration (SC) was 7.90 mg/L. The LC50 at 24 and 48 h of NH3-N were 8.396 and 5.298 mg/L respectively, and the SC was 0.63 mg/L. The LZM activity of each treatment group was significantly lower than that of C0 group (P<0.01) at 6, 24, 48, and 72 h. AKP and ACP activity of C10, C20, and C40 groups was significantly higher than that of control group at 24 h (P<0.05), while the SOD activity of the C20 group was significantly lower than that of other stress times (P<0.05). At 72 h, the PO activity of C30, C40, and C50 groups were significantly higher than that of C0 group (P<0.05). Under the experimental conditions, ammonia nitrogen that was lower than 40 mg/L could significantly enhance the AKP and ACP activity of S. paramamosain over a 24 h period, while 50 mg/L ammonia nitrogen had inhibitory effects. Ammonia nitrogen in all groups had significant inhibitory effects on LZM activity of S. paramamosain, which had no significant effect on SOD activity, but had an obvious enhancement effect on activity of PO by 72 h.