Immune response of shrimp Peneaus monodon against Vibrio parahaemolyticus

The study was carried out on impact of vibriosis by using Vibrio parahaemolyticus in Peneaus monodon Fabricius, 1798, collected from Nagapattinam. The impact was studied on heamatological and biochemical parameters. Feeds were prepared by coating probiotic strains of B. firmus and B. coagulans. Laboratory investigations were carried out concerning impact of pathogenic Vibrio parahaemolyticus of total count, differential count, Nitroblue tetrazolium activity, Prophenoloxidase activity and bacterial clearance in P. monodon. Total heamocyte was enumerated in vibriosis by induced shrimps, all results showing an increase in total haemocyte count after the time of infection. After feeding, the total heamocyte count was 1442 cells/cu·mm in control animals, in B. coagulans supplemented animals 2757 cells/cu.mm and in B. firmus was 2448 cell/cu·mm. After feed supplementation the shrimps were infected with V. parahaemolyticus and their impact on total haemocyte count was assessed in all three groups. In control, the total haemocyte count was increased with 2560 cells/cu·mm, whereas in B. coagulansis 5126 cells/cu·mm, and in B. firmusis 4697cells/cu·mm. Two-way Analysis of Variance for total haemocyte count in normal and infected haemolymph showed a significant variation. The control samples recorded the lowest, and after infection B. coagulans supplemented animals recorded maximum counts among three groups. Differential count was evaluated by studying the three types of cells. There was not much variation in the percentage of cells, but a slight decrease was observed in the hyaline cells after 24 hours of infection. The NBT activity was 1.4 (NBT activity) in control animals, 2.7 in B. coagulans and 2.4 in B. firmus supplemented animals. Maximum reduction was observed in control animals with 0.92, 1.7 in B. coagulans and 1.4 in B. firmus supplemented animals. There was an initial spurt of vibrios when cultured in selective medium TCBS in all three treatments and gradual decrease in the vibrios count during 24 hours observation.