【摘要】 研究了3种不同温度〔(19±1),(25±1),(31±1)℃〕条件下,不同浓度的鳗弧菌和白斑综合症病毒对凡纳滨对虾的致病性。实验分为合并感染组和单独感染组,各组在感染后0,6,12,24,48,72,96 h取样保存,观察记录对虾发病及死亡率,并定期检测病毒含量。结果表明:在温度(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11.1%,1.2×103 copy·g-1。在温度(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在显著差异(P<0.05),死亡率最大值为77.8%。在温度(31±1)℃条件下,各组累积死亡率在48 h开始升高,合并感染组死亡率和病毒增殖明显快于单独感染WSSV组。随着感染时间延长,单独细菌感染组随浓度升高,对虾死亡加快。因此,低温条件下,鳗弧菌和WSSV致病力不高,随着温度升高,合并感染的致病力随温度升高而升高,即温度能显著影响鳗弧菌和WSSV的致病力。更多还原

【Abstract】 Litopenaeus vannamei were infected separately or co-infected with Vibrio anguillarum and white spot syndrome virus( WSSV) at different concentrations under three different temperature conditions( 19 ± 1,25 ±1,31 ± 1 ℃). The infected L. vannamei were sampled at the 0,6 12,24,48,72,96 hrs after infection to observe and record their infection rate and mortality and determine their WSSV load. The cumulative mortality and WSSV load of L. vannamei infected were found lower than 11. 1% and 1. 2 × 103 copies / g,respectively during the experiment at the temperature of( 19 ± 1) ℃. At the temperature of( 25 ± 1) ℃ the cumulative mortality of L. vannamei was significantly different between the single infection of WSSV and the co-infection of WSSV and V. anguillarum at 48 h- 96 h( P < 0. 05),and between the co-infection groups( P < 0. 05),with the maximum mortality of the co-infection group at the concentration of 2. 3 × 106cfu·m L- 1being 77. 8%. At the temperature of( 31 ± 1) ℃,the cumulative mortality of L. vannamei in each infection group began to increase at 48 h,and the virus replication and the cumulative mortality of L. vannamei was significantly higher in the co-infection group than in the WSSV infection group. Therefore,V. anguillarum and WSSV had a low pathogenicity at the lower temperature. As the temperature increased,the pathogenicity of Vibrio anguillarum and WSSV in coinfection increased with the temperature. That means temperature could significantly affect the pathogenicity of V. anguillarum and WSSV.更多还原