Effect of different pH and salinity levels on the viability of Penaeus monodon baculovirus (MBV) in Penaeus semisulcatus

The virucidal effect of pH and salinity on Penaeus monodon baculovirus (MBV) was investigated by water borne inoculated methods exposing PL۱۲ Penaeus semisulcatus for ۱۰ hours and observing for ۱۰ days at temperature ۲۸- ۳۰°C. For this purpose, one thousand virus free PL۱۲ of P. semisulcatus were divided into five groups and each group placed in a ۱۰ L plastic basin containing chlorine-treated sea water at ۳۵ppt. The salinity of basins water after ۱۲ hours changed to ۵, ۱۰, ۲۰, ۳۰ and ۴۰ppt using synthetic sea salt. To study the effect of pH, solution with various pH of ۳, ۵, ۷, ۸, ۹ and ۱۲ were prepared using IN NaOH and IN HCL to Na۲HPO۴ solution. For transmission of MBV, an aliquot of approximately ۱۰ frozen infected larvae were used for each experiment by water born inoculated method. Ten hours after inoculation, the shrimp were removed from jar and introduced into another jar with the same salinity or pH. During ۱۰ days experiment, the rate of infection (ROI), severity of infection (SOI) and accumulative mortality were varied among the MBV-infected. Penaeus mondon baculovirus was able to infect Penaeus semisulcatus at salinity ranging from ۵-۴۰ppt whereas at pH ۳ and ۱۲, MBV was completely inactivated MBV was not able to infect larvae at pH ۵, ۷, ۸ and ۹.

Keywords:

Penaeus mondon , Baculovirus , Penaeus semisulcatus , Rate of infection (ROI) , Severity of infection (SOI) , Accumulative mortality , pH , Salinity