不同温度下哈维氏弧菌和白斑综合症病毒对凡纳滨对虾的致病性

Pathogenicity of Vibrio harveyi and white spot syndrome virus to Pacific white leg shrimp Litopenaeus vannamei at different temperature

在不同温度[(19±1)、(25±1)、(31±1)℃]条件下,研究了不同浓度哈维氏弧菌Vibrio harveyi和白斑综合症病毒(WSSV)对凡纳滨对虾Litopenaeus vannamei(体长8.12 cm±0.83 cm)的致病性。结果表明:温度为(19±1)℃时,整个试验过程中对虾死亡率均低于8.9%,各组病毒携带量低于3.9×104copy/g;温度为(25±1)℃时,病毒单独感染组对虾的死亡率和病毒携带量(最大值71.1%,1.9×105copy/g)和高浓度继发感染组的死亡率和病毒携带量(最大值77.8%,3.2×106copy/g)从试验中期开始明显高于其他组,死亡加快,病毒携带量迅速增加,单独感染细菌组死亡率随感染浓度的升高而升高(最大值为21.1%);温度为(31±1)℃时,病毒单独感染组的死亡率和病毒携带量(最大值47.8%,2.2×104copy/g)从试验中期开始明显低于继发感染组(最大值80.0%,6.1×106copy/g),单独感染细菌组的累积死亡率随细菌浓度的升高而升高(最大值24.4%)。研究表明,温度对WSSV和哈维氏弧菌的致病力影响显著,继发感染和细菌单独感染随温度的升高致病力升高,高温和低温对WSSV的致病力有抑制作用。

The pathogenicity of different concentrations of Vibrio harveyi and white spot syndrome virus（ WSSV） to Pacific white leg shrimp Litopenaeus vannamei with body length of（ 8. 12 ±0. 83） cm was studied at water temperature of（ 19 ±1）,（ 25 ±1）,and（ 31 ±1） ℃. Throughout the experiment,the cumulative mortality was found below 8. 9% in each group and the virus carrying amount was less than 3. 9 ×104 copy / g in each group at（ 19 ±1） ℃. At（ 25 ±1） ℃,however,the maximal cumulative mortality was 71. 1%,and the virus carrying amount 1. 9 ×105 copy / g in the singly-infected with WSSV group,from the mid-experimental,significantly higher in the high concentrations of secondary infection group（ the maximum 77. 8%,3. 2 ×106 copy / g） than in the other groups（ P〈0. 05）,with higher mortality（ the maximum 21. 1%） and virus carrying. The maximal cumulative mortality of47. 8%,and the virus carrying amount of 2. 2 ×104 copy / g were found in the singly-infected with WSSV group at（ 31±1） ℃,significantly lower than in the secondary infection group（ the maximum 80. 0%,6. 1×106 copy / g）.There was increase in mortality（ the maximum 24. 4%） with elevated concentration of Vibrio harveyi in the singlyinfected with Vibrio harveyi group. The findings indicate that the pathogenicity of Vibrio harveyi and WSSV is significantly affected by temperature,and that the pathogenicity of the secondary infections and the singly-infected with Vibrio harveyi were found to be increased with raising temperature. The pathogenicity of WSSV was shown to be inhibited by high and low temperature.