中文摘要：

为探讨亚硝酸盐急性胁迫对中华绒螯蟹机体免疫力的影响,以及机体在胁迫过程中的应对策略,分别测定了幼蟹（平均体重3.25 g）在10、20、30、40 mg L-1亚硝酸盐暴露组和对照组中血细胞总数（Total hemocyte counts,THC）、超氧化物歧化酶（Superoxide dismutase,SOD）活力、丙二醛（Malodiadehyde,MDA）含量以及热休克蛋白70（Heatstress protein 70,HSP70）表达量在受胁迫2 d内的动态变化.结果表明：1）低浓度亚硝酸盐（10 mg L-1）胁迫组THC在胁迫3 h时显著高于对照组,肝胰腺中SOD活性在胁迫3 h和6 h时亦显著提高,表现出一定的＂毒物兴奋效应＂.2）但随着暴露时间的延长和亚硝酸盐浓度的升高,幼蟹THC减少,肝胰腺SOD活性下降,而MDA含量升高.3）对照组中有少量的HSP70表达.幼蟹经10、20 mg L-1亚硝酸盐处理后,鳃组织中HSP70表达量在胁迫6 h后达到最大,而经30、40 mg L-1亚硝酸盐处理后,HSP70表达量在胁迫3 h后达到最大.各浓度组所诱导的HSP70最大表达量与水中亚硝酸盐的浓度呈正相关.以上结果说明亚硝酸盐胁迫可通过加剧组织中脂质过氧化的方式导致机体免疫力下降,肝胰腺中MDA的含量变化可作为亚硝酸盐胁迫的有效评价指标之一,而HSP70表达量的变化可作为早期预警指标应用于亚硝酸盐胁迫评价中.图2表1参36

英文摘要：

Nitrite is an intermediate product either in the bacterial nitrification of ammonia,or in the bacterial denitrification of nitrate.The concentration of nitrite may reach 50 mg L-1 in intensive aquacultural systems due to an imbalance in biofilter resulting from overcrowding effect and poor water recirculation.High levels of nitrite in water were potential factors triggering stress on aquatic organisms.The sensitive indicators of stress evaluation for the Chinese mitten-hand crab Eriocheir sinensis were selected to investigate the effect of ambient nitrite on the immunity response.In this experiment,the juvenile crabs（mean weight： 3.25 g） were divided into four nitrite exposed groups（10,20,30 and 40 mg L-1 ambient nitrite concentrations） and control group.The total hemocyte counts（THC）,superoxide dismutase（SOD） activity,malodiadehyde（MDA） level and HSP70 expression were measured after 3 h,6 h,1 d,and 2 d stress.The results were showed as follows： 1） After treated in low concentration（10 mg L-1） nitrite exposure,THC increased significantly at 3 h and SOD activity in hepatopancreas increased significantly at 3 h and 6 h compared with the control group,which indicated a poison-intoxication effect.2） With time elapsing and ambient nitrite increasing,THC and SOD activity in hepatopancreas decreased while MDA level in hepatopancreas incread,which indicated accelebrating effect of lipid peroxidation by nitrite exposure.3） HSP70 could be expressed at a low level in gills of crabs in the control group.The HSP70 expression reached a peak at 6 h stress when exposed in 10 and 20 mg L-1 nitrite and at 3 h stress when exposed to 30 and 40 mg L-1 nitrite.The maximum expression was positively correlated with the concentration of ambient nitrite.Therefore,nitrite stress played a mainly role in decreasing of immunity by accelerating lipid peroxidation.The level of MDA in hepatopancreas was an effective indicator and HSP70 expression in gills also could be an early indicator of nitrite stress.Fig 2,