白斑综合症病毒在日本囊对虾精养池塘中的动态变化

Variation in WSSV in Kuruma Shrimp Marsupenaeus japonicas Cultured and Zooplankton in Intensive Farming Ponds

用实时荧光定量PCR技术检测了高密度精养池塘中日本囊对虾体内及浮游动物白斑综合症病毒携带量的动态变化,检测结果显示,两口池塘的日本囊对虾苗种均携带白斑综合症病毒,达2.43×10~5~9.42×10~5 IU/mg;浮游动物也携带微量白斑综合症病毒,达6.78×10~2~8.02×10~2 IU/mg。在整个养殖过程中,日本囊对虾多个组织均携带白斑综合症病毒,平均病毒量为鳃>肌肉>肝胰腺>胃;各组织病毒携带量的变化趋势不一致,肌肉、肝胰腺、胃等呈现明显的先降后升趋势,最低降至1.78×10~3 IU/mg,鳃白斑综合症病毒携带量的下降幅度较小,最低为7.29×10~4 IU/mg。浮游动物的病毒量在白斑综合症爆发前波动不明显,发病时急剧升高。综合认为,苗种携带是白斑综合症病毒的主要来源;当养殖进入中后期,底质变差、水温降至病毒适宜复制的温度时,易爆发白斑综合症。

The variation in white spot syndrome virus(WSSV)infection intensity of kuruma shrimp Marsupenaeus japonicas and zooplankton were quantified in intensive farming ponds by real-time PCR.The results showed that the shrimp larvae in the ponds carried WSSV at concentrations from 2.43×10~5 to 9.42×10~5 IU/mg;the zooplankton carried WSSV at concentrations from 6.78×10~2 to 8.02×10~2 IU/mg.Four tissues(gill,muscle,stomach and hepatopancreas)of kuruma shrimp carried WSSV genomes through the entire farming perid.The maximal mean number of WSSV copies were observed in the gill and the minimal mean number of WSSV copies in the stomach.The variation of WSSV in the tissues was different.The variation in amounts of WSSV genome showed first decrease then increase in the tissues(muscle,stomach and hepatopancreas)with the minimal value 1.78×10~3 IU/mg.The WSSV genome amount in the gill was decreased,less than the other tissues,with the minimal value of 7.29×10~4 IU/mg.The amounts of WSSV in the zooplankton had no obvious fluctuation before the breakout of WSS,and increased rapidly after the breakout of WSS.The findings indicated that the main source of WSSV in the ponds was shrimp seed;WSS was easily outbreak during the middle and later rearing periods,when the sediment was polluted and the water temperature decreased at the WSSV vulnerable temperature of kuruma shrimp.