中国对虾(Fenneropenaeus chinensis)和凡纳滨对虾(Litopenaeus vannamei)对白斑综合征病毒的敏感性比较

摘要

In the present study, we applied the quantitative feeding method to compare the sensitivity to WSSV infection of shrimp species including Wild Fenneropenaeus chinensis (W-Fc), Selected Fenneropenaeus chinensis (S-Fc) and Commercial Litopenaeus vannamei (C-Lv). We found that the average survival time after being fed with equal amount of WSSV-loaded baits was (124.11±39.49) h, (166.79±51.54) h and (136.90±41.99) h for W-Fc, S-Fc and C-Lv respectively, which were significantly different among the three groups (P<0.05). The death peak of W-Fc appeared at 96 h after infection and continued to 216 h, and the death peaks of C-Lv and S-Fc occurred at 144 h after infection. The quantity of virus in muscles of living shrimp samples was examined with absolute quantitative PCR at eight time points (3 h, 6 h, 12 h, 24 h, 36 h, 48 h, 72 h, and 144 h). The virus loads in W-Fc, S-Fc, and C-Lv at 48 h were (1.22×106±6.14×105), (7.10×103±7.26×102), and (1.50×104± 4.19×103) copies/ng DNA respectively. At 144 h, the virus loads in the three groups of shrimps were (8.44×106±1.25×106), (3.21×106±8.21×105), and (1.49×106±6.59×105) copies/ng DNA respectively. These results indicated that W-Fc was more sensitive to WSSV, and that S-Fc had higher resistance to WSSV. It suggested that S-Fc and C-Lv had different sensitivity to WSSV infection and thus might have distinct immune mechanisms against WSSV. S-Fc showed higher resistance to WSSV, implying that the resistance to WSSV was well improved in"Huanghai No.2" through long-term artificial selection. Therefore, an effective way to prevent and treat WSSV is selective breeding, which could greatly reduce the damage of WSSV disease.%本研究分别对中国对虾野生群体(Wild-Fenneropenaeus chinensis, W-Fc)、中国对虾选育群体'黄海2号'(Selected-Fenneropenaeus chinensis, S-Fc)和凡纳滨对虾商业一代苗种(Commercial-Litopenaeus vannamei, C-Lv)采用单尾定量口饲感染白斑综合征病毒(WSSV),比较W-Fc、S-Fc及C-Lv对WSSV的敏感性差异.结果显示,感染同等含量WSSV后,W-Fc、S-Fc和C-Lv的平均存活时间分别为(124.11±39.49) h、(166.79±51.54) h和(136.90±41.99) h,3组对虾间的平均存活时间存在显著性差异(P<0.05).3组对虾在感染期间的死亡趋势:W-Fc在96 h达到死亡高峰,并且一直持续到216 h;S-Fc和C-Lv在144 h出现死亡高峰.另外,分别在感染后的3、6、12、24、36、48、72、144 h共8个时间点对3组对虾进行活体取样,利用实时荧光定量RT-PCR技术对其进行了病毒载量检测,从对虾存活时间和体内肌肉组织病毒载量的角度比较不同对虾抗病性能的差异,结果如下:48 h 时,W-Fc、S-Fc 和 C-Lv3对虾体内肌肉组织的病毒载量分别为(1.22×106±6.14×105)、(7.10×103±7.26×102)和(1.50×104± 4.19×103) copies/ng DNA;144 h时,3组对虾体内肌肉组织病毒载量分别为(8.44×106±1.25×106)、(3.21×106±8.21×105)和(1.49×106±6.59×105) copies/ng DNA.实验结果显示,3组对虾对WSSV敏感性从高到低依次为中国对虾野生群体、凡纳滨对虾商业苗种、中国对虾选育群体,表明中国对虾选育群体'黄海2号'在人工感染WSSV条件下表现出了良好的抗病性能.