The Comparison of the Sensitivity to the White Spot Syndrome Virus Between Fenneropenaeus chinensis and Litopenaeus vannamei

Abstract:

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.