Immunomodulatary Potential of Chitosan and Levamisole Against Bacterial Diseases of Penaeus monodon

Effective eco-friendly disease management strategies are emerging as important criteria for sustainable shrimp farming due to problems such as development of resistant microbial strains by application of antibiotics and other chemo-therapeutants. Vaccine development for the crustaceans is impractical due to lack of specific immune system. However, the non-specific immunity can be enhanced using immunostimulants. They enhance the microbicidal activity of haemolymph and phagocytosis of the cells. Studies were made to evaluate the immunomodulating effects of chitosan and levamisole. Different parameters such as growth and survival stimulating potency, hematological index, phagocytic index and bacterial clearance were studied. Significant increment in the growth and immune index were noted in the shrimps fed with levamisole 150 groups. Challenge experiments were made with commercially important shrimp pathogens Vibrio harveyi in both control and experimental shrimps and 100% mortality observed in the control group, but in the experimental diet administered group showed protection in a considerable manner.