为探讨亚硝态氮胁迫对草鱼(Ctenopharyngodon idellus)非特异性免疫性能的影响,将草鱼(0.15 ±0.05 g)分别暴露在0 mg/L、0.2 mg/L、0.4 mg/L、0.8 mg/L、1.0 mg/L、2.0 mg/L、4.0 mg/L和8.0 mg/L的亚硝态氮溶液中,分别在暴露后Od、1d、4d、7d测定草鱼体内补体C3和C4含量、超氧化物歧化酶(SOD)活力、谷胱甘肽(GSH)含量以及y-谷氨酰半胱氨酸合成酶(y-GCS)活性.结果表明,亚硝态氮胁迫对草鱼非特异性免疫性能产生了消极影响,其胁迫效应随着暴露浓度的不同而表现出不同的特性.当暴露浓度低于1.O mg/L时,补体C3和C4含量维持正常水平或显著升高；但暴露浓度超过1.0 mg/L,补体C3和C4含量水平会显著下降.SOD活性随着暴露时间而显著升高,但高浓度暴露使SOD活性在暴露7d时显著下降.y-GCS活性一般都随着暴露时间延长而显著升高,虽然暴露后期其活性下降,但还是显著高于对照组.而GSH含量在暴露4d时显著升高,低浓度组(＜1.0 mg/L)在7d时恢复至对照水平.%In order to evaluate the effects of nitrite on non-specific immune responses in Ctenopharyngodon idellus,C.idellus (0.15 ± 0.05 g) were exposed to eight experimental groups (0,0.2,0.4,0.8,1.0,2.0,4.0,and 8.0 mg nitrite per liter).The concentrations of complement C3 and C4,glutathione (GSH) content,and the activity of superoxide dismutase (SOD) as well as γ-gutamylcysteine synthetase (γ-GCS) were assayed at 0 d,1 d,4 d and 7 d respectively after exposure.The results showed that acute nitrite exposure exerted deleterious effect on the non-specific immune function of grass carp.The concentrations of complement C3 and C4 were at the normal level or a significantly higher level when the nitrite concentration was below 1.0 mg/L However,the concents of complements decreased significantly as the nitrite concentration above 0.1 mg/L.The activity of SOD increased significantly over the exposure time,while dropped significantly at 7 d after exposure in higher dose groups.The activity of γ-GCS generally increased significantly with exposure time,though it decreased at the late of exposure the teratments.The concentration of GSH in fish exposed to nitrite was significantly higher than that in control group at 4 d,but returned to control level at 7 d after exposure when the nitrite concentration was below 1.0 mg/L.
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