亚硝酸氮浓度变化对感染白斑综合症病毒的凡纳滨对虾的影响

Effects of Concentration Changes of Nitrogen Nitrite on Litopenaeus vannamei Infected with White Spot Syndrome Virus

[目的]为对虾产业的健康可持续发展提供依据.[方法]研究不同亚硝酸氮浓度变化对感染WSSV的凡纳滨对虾的影响.[结果]先感染WSSV试验中,亚硝酸氮浓度在渐变和突变过程中对凡纳滨对虾累积死亡率及病毒增殖的影响显著（P＜0.05）.突变试验中起始浓度、中浓度、高浓度组凡纳滨对虾的累积死亡率分别为52.2％ 、70.0％和76.7％,病毒含量分别为7.0×10^6、1.2×107和9.4×10^6copy/g;渐变试验中累积死亡率分别为50.0％、63.3％和66.7％,病毒含量分别为4.7×10^6、2.7×10 7和1.1 × 10^7 copy/g.后感染WSSV试验中24h对虾死亡率低于12.2％,48h后突变组首先出现死亡高峰,72 ～ 120 h存在显著差异（P＜0.05）;渐变组试验中起始、中、高浓度亚硝酸氮组凡纳滨对虾的死亡率分别为21.1％、30％和50％,病毒含量分别为9.8×10^4 、2.2×105和2.3×10v6 copy/g;突变组试验中凡纳滨对虾的死亡率分别为31.1％ 、48.9％和61.1％,病毒含量分别为2.7×10^5、2.1×10^6和5.2×10^6 copy/g.[结论]携带WSSV的凡纳滨对虾对亚硝酸氮浓度变化更敏感,更易引起WSSV从潜伏感染转为急性感染.亚硝酸氮突变影响对虾对WSSV的易感性比渐变更为显著.

[ Objective ] The research aimed to provide basis for the healthy and sustainable development of shrimp industry. [ Method] The effects of different concentration changes of nitrogen nitrite on Litopenaeus vannamei infected with WSSV were studied. [ Result] In the earlier test of WSSV infection, the concentration of nitrogen nitrite in the gradual change and sudden change process had significant effects on the cumulative mortality of L. vannamei and WSSV proliferation（ P 〈 0.05 ）. In the sudden change test,the cumulative mortality of L. vannamei in original concentration,medium concentration and high concentration groups of nitrogen nitrite were 52.2% ,70.0% and 76.7% respectively and the virus contents were 7.0 × 10^6 , 1.2 × 10^7 and 9.4 × 10^6 copy/g respectively. In the gradual change test,the cumulative mortality of L. vannamei were 50.0% ,63.3% and 66.7% respectively, and the virus content was 4.7 × 10^6 , 2.7× 10^7 and 1.1 × 10^7 copy/g respectively. In later test of WSSV infection, 24 h mortality of L. vannamei was less than 12.2% , and the peak mortality appeared in sudden change group after 48 h and the mortality during 72 - 120 h had significant difference （ P 〈 0.05 ）. In the gradual change test,the mortality of L. vannamei in original concentration,medium concentration and high concentration groups of nitrogen nitrite were 21.1% , 30% and 50% respectively and the virus content were 2.7 × 10^5 , 2.1 × 10^6 and 5.2 × 10^6 copy/g respectively. In the sudden change test, the mortality of L. vannamei were 31.1% , 48.9% and 61.1% respectively,and virus content were 2.7 × 10^5 , 2.1 × 10^6 and 5.2 × 10^6 copy/g respectively. [ Conclusion] L. vannamei infected with WSSV were more sensitive to the changes of nitrite concentration, which was easily caused WSSV from latent infection into acute infection. Sudden changes of nitrogen nitrite had more significant effects on the susceptibility of L. vannamei to WSSV than gradual changes.