Immune Priming Response Induced by Heat-Inactivated WSSV on Fenneropenaeus chinensis at Different Temperature

Abstract:

This study was designed to explore whether the heat-inactivated WSSV could induce immune priming response on Fenneropenaeus chinensis. During the initial 6 days, four experiment groups (E15℃, E23℃, E28℃, and E32℃) were fed with typical symptoms of WSSV prawn muscle, which was dealt with at 60℃ for 1 h using the equivalent and quantitative test method. At the same time, we set a positive control group C23℃ (fed with the unheat-inactivated WSSV muscle) and a control group CF23℃ (fed with commercial compound feed only). At the 13th day of the experiment, all shrimps were infected with WSSV again. The result showed that 60℃ could decrease the activity of WSSV absolutely, there were no dead shrimp in the initial 12 d, but the mortality of positive control group C23℃ was 100%. The survival rates of different experiment (E15℃, E23℃, E28℃, and E32℃) and control groups were 80.41%, 33.29%, 8.47% , 16.43% and 8.89%, respectively, after 19 days. The survival rate of E15℃ showed highly significant difference from other experiments (P<0.01). In addition, there was a significant difference between E23℃ experiment group and other experiment groups (P<0.05). Nevertheless, there was no significant difference between E28℃ and E32℃ groups (P>0.05). Compared to the results of absolute quantitation, it was found that the multiplication rate of WSSV was the highest under 28℃, high (32℃) and low (15℃) temperature would inhibit the multiplication of WSSV in the shrimps which accepted the subsequent rechallenge of WSSV after the heat-inactivated WSSV induced. Experimental results showed that heat-inactivated WSSV could induce immune priming response and provide some protection to the infected shrimp by WSSV. The multiplication rate of WSSV is closely related to temperature.