摘要
为探索亚硝态氮(NO-2-N)胁迫与罗非鱼(Oreochromis niloticus)海豚链球菌(Streptococcus iniae)病爆发的关系,揭示罗非鱼海豚链球菌病爆发的环境机制,研究了不同质量浓度NO-2-N(<0.01、0.75、1.50、3.00和5.00mg.L-1)胁迫下罗非鱼对海豚链球菌的易感性及罗非鱼血清超氧化物歧化酶(SOD)活性的响应。结果表明,感染海豚链球菌的罗非鱼死亡率随NO-2-N浓度的升高而升高,并与暴露时间呈显著正相关(P<0.05),在暴露12～13 d时死亡率达到稳定状态,<0.01 mg.L-1浓度组在暴露13 d时,0.75、1.50、3.00和5.00 mg.L-1浓度组在暴露12 d时累积死亡率分别为20.00%、23.33%、30.00%、43.33%和46.67%。罗非鱼血清SOD活性随NO-2-N浓度的升高而降低,试验期间≤1.50 mg.L-1NO-2-N处理组血清SOD活性与对照组相比差异均始终未达显著水平(P>0.05),试验48、96和120 h时≥3.00 mg.L-1NO-2-N处理组血清SOD活性显著低于对照组(P<0.05)。认为高质量浓度(≥3.00 mg.L-1)NO-2-N能够显著降低罗非鱼的免疫力,增加其对海豚链球菌的易感性。
In order to explore relationship between nitrite nitrogen and outbreak of Streptococcus iniae disease among tila- pia （Oreochromis niloticus GIFT） and environmental mechanism of the outbreak, studies were carried out on susceptibility of the fish to the disease under the stress of nitrite nitrogen varying in concentration （ 〈 0. 01, 0. 75, 1.50, 3.00, and 5.00 mg ·L^-1） , and response of serum superoxide dismutases （SODs） in the fish in activity, which is an index of the fish＇s serum immunity enzymes. Results show that mortality of the fish exposed to the disease rose with the concentration of nitrite nitrogen and the duration of the exposure （ P 〈 0. 05 ） , and leveled off after 12 to 13 days of exposure, reaching 20. 00% , 23.33% , 30. 00% , 43.33% , and 46. 67% , respectively, in groups of fish exposed to 〈 0. 01 , 0. 75, 1.50, 3.00, and 5.00 mg ·L^-1 nitrite nitrogen. Serum SOD activity in tilapia declined with the rising concentrations of nitrite nitrogen. In Treatment ≤ 1.50 mg ·L^-1 NO2- -N, SOD activity of the fish was lower than that in the control, but the difference never reached a significant level （ P 〉 0. 05 ） in the experiment. However, after 48, 96 and 120 hours of expo- sure, SOD activity was much lower in Treatment ≥3.00 mg ·L^-1NO2- -N than in the control. It is, therefore, held that high concentrations of nitrite nitrogen （≥3.00 mg ·L^-1 can significantly ＇affect immunity of the fish, thus increasing its susceptibility to the disease of Streptococcus iniae.
出处
《生态与农村环境学报》
CAS
CSSCI
CSCD
北大核心
2013年第1期106-109,共4页
Journal of Ecology and Rural Environment
基金
现代农业产业技术体系建设专项(CARS-49)
关键词
罗非鱼
海豚链球菌
NO2-N
免疫力
易感性
Oreochromis niloticus GIFT
Streptococcus miae
nitrite nitrogen
immunity
susceptibility
