不同温度条件下溶壁微球菌和白斑综合症病毒对凡纳滨对虾的致病性

The Pathogenicity of Micrococcus lysodeikticus and White Spot Syndrome Virus to Litopenaeus vannamei under Different Temperature Conditions

研究在3种不同温度（19±1℃、25±1℃、31±1℃）条件下不同浓度的溶壁微球菌和白斑综合症病毒对凡纳滨对虾的致病性。通过单独及合并感染对虾记录其死亡率并检测病毒携带量。结果显示：温度19±1℃条件下，至实验结束各组累积死亡率和病毒携带量分别低于7.7%，8.6×10^2 copy/g。温度25±1℃条件下，48～96 h单独感染WSSV累积死亡率与合并感染组差异显著（P＜0.05），而且合并感染组不同浓度之间存显著差异（P＜0.0^5），死亡率和病毒量最大值分别为71.1%，6.2×10^5 copy/g（合并感染浓度9.5×10^7 cfu/mL组）。温度31±1℃条件下，各组累积死亡率在48 h迅速升高，合并感染组死亡率和病毒携带量（最大值：75.6%，2.0×10^6 copy/g）明显高于单独感染WSSV组（42.2%，2.2×10^4 copy/g）。随着感染时间延长，单独细菌感染组对虾死亡率随感染浓度升高而升高（最大值：71.1%）。因此合并感染对对虾养殖危害更大，且随着温度升高，溶壁微球菌和合并感染的致病力随温度升高而升高，即温度能显著影响溶壁微球菌和WSSV的致病力。

Explored the pathogenicity of different concentrations of Micrococcus lysodeikticus and White Spot Syndrome Virus to Litopenaeus vannamei under three different temperature conditions （19±1 ℃, 25±1 ℃, 31±1 ℃）. The paper recorded the mortality and detect viral load in vannamei by singal or combined infection with two pathogens. The results showed that when the temperature was 19 ±1 ℃, the cumulative mortality and viral load of each group were respectively lower than 7.7%and 8.6×10^2 copy/g;When the temperature was 25± 1 ℃, there was a significant difference between the WSSV single-infection group and co-infection group at 48-96 h（P〈0.05） , and there was also a remarkable disparity between co-infection group in different concentra-tions （P〈0.05） with the maximum mortality and viral load of 7.7%and 6.2×10^5 copy/g （under the concentration of 9.5×10^7 cfu/mL）. Under the condition of 31±1℃, the cumulative mortality of each group rose rapidly at 48 h. The mortality and virus carrying amount of co-infection group（max：75.6%,2.0×10^6 copy/g） were obviously higher than the single-infection ones（42.2%,2.2×10^4 copy/g）. As the time of infection prolonged, the mortality caused by single-infection group grew with the increase of virus concentration （mortality max： 71.1%）. Therefore, co-infection is more harmful than single ones. What is more, the pathogenicity of M. lysodeikticus and co-infec-tion group on L. vannamei′s breeding increase as the temperature goesd up, from which we learned that tem-perature could significantly affect the pathogenicity of M. lysodeikticus and WSSV.