Considering this potential threat of disease on one hand and the environmental issues on the other hand, the disease management aspects should concentrate on eco-friendly methods. During disease outbreak, immunostimulants helps to elevate the nonspecific defense mechanism, and thus prevent losses from diseases. Microbial and herbal active compounds had enhanced the nonspecific immunity in fishes and shrimp. Immunostimulants and their application in elevating the defense system in shrimp and crustaceans has gained much importance. Herbal plants are the storehouses and rich sources of safer and cheaper chemical compounds.
Emerging evidence indicates that herbal plants exert their beneficial effects on animal immune system mostly by plant secondary metabolites. The beneficial effect of plant products is reducing the stress condition, serving as an appetizer, rendering antimicrobial activity as well as stimulating the immune system. These natural plant products have been reported to have various activities like anti-stress, growth promoters, appetizer, tonic, immunostimulants and antimicrobials. Plant and microbial products are used as immunostimulants, which can elevate the nonspecific immunity in shrimp.