Administration of marine algae (Gracilaria verrucosa) immunostimulant enhances some innate immune parameters in black tiger shrimp (Penaeus monodon Fabricus) against Vibrio harveyi infection

The marine algae (Gracilaria verrucosa) immunostimulant (MAGVI) was extracted with PBS and screened against the pathogen Vibrio harveyi isolated from the infected Penaeus monodon Fabricus. Immune parameters, which included total haemocyte count (THC), superoxide anion, protease activity and cumulative mortality were determined in the black tiger shrimp that had been incubated by dipping method in MAGVI concentrations were 1, 1.5 and 2 ppt for 3 hours. All data were collected 3 hours after deeping in MAGVI treatment, after 24 hours Vibrio harveyi infection and 6-day recovery after Vibrio harveyi infection for 24 hours. The results showed that, compared with those in control group, all treatments resulted in significant increase in amount of THC, superoxide anion, protease activity and cumulative mortality (p<0.05). These results indicated that MAGVI might elevate the function of immunity in black tiger shrimp (Penaeus monodon Fabricus).