EFFECT OF IMMUNOSTIMULANT ON ENHANCEMENT OF THE IMMUNE RESPONSE OF KURUMA SHRIMP Marsupenaeus japonicus AND ITS RESISTANCE AGAINST WHITE SPOT SYNDROME VIRUS (WSSV)

An experiment of 45 days duration to test the efficacy of the Vibrio alginolyticus as an immunostimulant was conducted in Marsupenaeus japonicus against white spot syndrome virus (WSSV) infection, considered as one of the serious pathogens of shrimps. The shrimps were fed with the experimental diets coated with different concentrations of bacteria of 17 ml / kg feed and 10 % of animal body wt. They were challenged with WSSV to assess the increase in survival rate and growth if any due to immune enhancement. Another group of shrimp was used for drawing the haemolymph to estimate the increase in the level of prophenoloxidase activity. Samplings for the above said analysis were carried out at 15 days interval for a period of 45 days. The highest prophenoloxidase activity (39.78 with sand substrate-T1) and the highest survival rate (66.66 % with sand substrate-T1) and highest growth rate (7.04 % in 17ml/kgwith sand substrate-T1) were recorded in experimental diet (17 ml / kg feed). Hence the 17 ml / kg feed of Vibrio alginolyticus formalin killed added to the diet could be an eco-friendly and economically viable immunostimulant for penaeid shrimps.