中文摘要：

15℃下将体质量（85.51±16.18）g的日本蟳暴露于对照及低质量浓度（2.0、4.0mg/L）、中质量浓度（6.0mg/L）和高质量浓度（8.0、10.0mg/L）的亚硝态氮中,于胁迫的第1、3、5、10、15d取血,测定其免疫的相关指标,以研究亚硝态氮质量浓度对日本蟳免疫功能的影响。试验结果表明,在亚硝态氮胁迫下,所测指标均呈＂先升后降＂的趋势。在胁迫第1d,各试验组的血细胞密度、血蓝蛋白含量及溶菌酶、超氧化物歧化酶、过氧化氢酶活力均大于对照组,而高质量浓度组的酚氧化酶活力低于对照组。随着亚硝态氮胁迫时间的延长,低质量浓度组血细胞密度和溶菌酶活力上升较快,而高质量浓度组酚氧化酶、超氧化物歧化酶和过氧化氢酶活力上升较快。低质量浓度组的血细胞密度和过氧化氢酶活力升高幅度较大,高质量浓度组的血蓝蛋白含量及酚氧化酶、溶菌酶、超氧化物歧化酶活力升高幅度较大。胁迫第10d,各试验组溶菌酶、超氧化物歧化酶和过氧化氢酶活力显著低于对照组（P〈0.05）。胁迫第15d,低质量浓度组血细胞密度、2.0mg/L组的血蓝蛋白含量、低质量浓度组和中质量浓度组的酚氧化酶活力略大于对照组,其他各指标所测结果均低于对照组。各试验组溶菌酶、超氧化物歧化酶和过氧化氢酶胁迫后活力与亚硝态氮胁迫质量浓度呈负相关,10.0mg/L组的3种酶活力分别比对照组降低95.41%、36.84%和77.78%。

英文摘要：

In the present study,the effects of nitrite-N levels,which were prepared by NaNO2,on the immune response of Japanese swimming crab Charybdis japonica were investigated.The crabs were allocated to five groups which was exposed to different nitrite-N levels：LC group（2.0 and 4.0 mg/L）,MC group（6.0 mg/L）and HC group（8.0 and 10.0 mg/L）.The relative immunity indicators in the haemolymph were measured on days 1,3,5,10 and 15 following the stress.All the measured indices were found to have a decline after an initial ascent.There were higher hemocyte concentration（DHC）,and hemocyanin contents,and lysozyme（LSZ）,superoxide dismutase（SOD） and catalase activities 1 day after nitrite-N exposure than those in the control group was while the phenoloxidase（PO） activity in HC group was decreased compared with the control group.With time elapsed,DHC level and LSZ activity in LC group were increased more rapidly while PO,SOD and CAT activities in HC group were increased more rapidly than in other treatments.Some parameters were increased to a greater extent,such as DHC account and CAT activity in LC group,PO,LSZ and SOD activities in HC group.On day 10,LSZ,SOD and CAT activities were significantly lower in the treatments than those in the control（P〈0.05）.On day 15,all parameters were found decrease compared with the control except DHC in LC group,the hemocyanin content of the group under the nitrite-N stress of 2.0 mg/L,the PO activity in LC and MC groups.LSZ,SOD and CAT activities in the treatments were found negatively related to the nitrite-N concentration on day 15,decreased by 95.41%,36.84%,and 77.78%,in the 10.0 mg/L group compared to the control group,respectively.