Protection of Penaeus monodon against white spot syndrome virus by inactivated vaccine with herbal immunostimulants.

To improve the immune response in tiger shrimp Penaeus monodon against WSSV infection, juveniles (350 ± 10 mg) were vaccinated with formalin-inactivated WSSV and fed with herbal immunostimulants. The methanolic extracts of herbal immunostimulants such as Acalypha indica, Cynodon dactylon, Picrorrhiza kurrooa, Withania somnifera and Zingiber officinalis were incorporated in formulated diets at different concentrations; 250 (ED(1)), 500 (ED(2)), 1000 (ED(3)) and 2000 (ED(4)) mg kg(-1) of feed and fed for 60 days after vaccination. After 30 and 60 days intervals of feeding, the shrimps were challenged with WSSV, which were isolated and propagated from the infected crustaceans.