氨氮胁迫与恢复对罗氏沼虾幼虾非特异性免疫的影响

Effects of ammonia-N stress and post-exposure recovery on nonspecific immunity of Macrobrachium rosenbergii juveniles

在温度为(25±1)℃、p H为8. 0±0. 5条件下采用生物毒性实验方法研究了氨氮对罗氏沼虾(Macrobrachium rosenbergii)幼虾半致死浓度,并设置0、0. 43、0. 64、0. 85、1. 06 mg·L^(-1)5个浓度研究氨氮胁迫48 h及恢复48 h对罗氏沼虾非特异性免疫的影响。结果显示:非离子氨对罗氏沼虾幼虾24、48、72、96 h半致死浓度分别为4. 25、2. 35、1. 86、1. 54 mg·L^(-1),安全浓度为0. 154 mg·L^(-1)。氨氮胁迫48 h,罗氏沼虾SOD活性显著升高(P <0. 05),而CAT和GSH-Px活性变化不显著(P> 0. 05); 0. 43、0. 64、1. 06 mg·L^(-1)氨氮胁迫组罗氏沼虾MDA含量显著高于对照组(P <0. 05)。氨氮胁迫后恢复48 h,各组SOD活性均较胁迫时显著下降(P <0. 05),但除0. 85 mg·L^(-1)组外的其它试验组仍显著高于对照组(P <0. 05); 0. 85、1. 06 mg·L^(-1)组CAT活性较胁迫状态显著下降(P <0. 05);试验组与对照组MDA含量无显著差异(P> 0. 05)。结果表明,低浓度氨氮短期胁迫对罗氏沼虾造成的氧化损伤在解除胁迫后可修复,但肌肉仍处于应激状态。

Current study explored the influence of ammonia-N stress and post-exposure recovery on the non-specific immunity of M.rosenbergii.The prawns were exposed to different concentrations of ammonia(0,0.43,0.64,0.85,1.06mg·L^-1)for48h,and then post-exposure recovery for48h was analyzed.The activities of superoxide dismutase(SOD),catalase(CAT),glutathione peroxidase(GSH-Px)and malondialdehyde(MDA)content were assessed in the muscle of M.rosenbergii under ammonia stress for48h and post-exposure recovery for48h.The results showed that the half lethal concentrations of non-ionic ammonia of24h,48h,72h and96h were4.25,2.35,1.86,1.54mg·L^-1,respectively.And the safe concentration was0.154mg·L^-1under the condition of(25±1)℃,pH8.0±0.5.The SOD activity in the muscle of M.rosenbergii was significantly raised by ammonia nitrogen at48h.However,compared to the control,the activities of CAT and GSH-Px in all ammonia treatments didn’t change significantly at48h(P>0.05).The MDA content of0.43,0.64,1.06mg·L^-1ammonia treatments were significantly higher than that of the control at48h(P<0.05).After48h post-exposure recovery,compared to the ammonia exposure,SOD activity reduced significantly with the same ammonia treatment(P<0.05),but they were still significantly higher than that of the control group except for0.85mg·L^-1(P<0.05).CAT activities in0.85,1.06mg·L-1treatments reduced significantly at the same ammonia treatments after48h post-exposure recovery(P<0.05),and MDA content of all treatments returned to the level of the control.The results indicate that oxidative damage of M.rosenbergii by ammonia-N recovers after48h post-exposure recovery,but oxidative stress still exists in the muscle.