Development of biofilm of Vibrio alginolyticus for oral immunostimulation of shrimp

Biofilm (BF) of Vibrio alginolyticus was developed on chitin flakes. BF formation was studied at various nutrient concentrations and incubation time. Highest colony-forming units of BF cells were obtained with 0.15% trypticase soya broth and at 3 days of incubation. The BF cells could be completely inactivated at 80A degrees C in 10 min and with 10% formalin in 24 h. SDS-PAGE profile of BF cells revealed repression of four proteins and expression of three new proteins compared to free cells (FC). The preliminary immune response studies showed that BF cells were superior to FC in stimulating the non-specific immune response of Penaeus monodon.