The use of immunostimulatory substances in fish and shellfish farming

Abstract

Abstract A number of different compounds with highly diverse chemical structures have been shown to elevate the overall resistance of animals to a number of infectious agents simultaneously. Such compounds, usually called immunostimulants, include bacterial cell wall fragments, s‐1,3‐glucans of yeast and mycelial fungi, peptides, and a number of synthetic products. The present review paper describes the chemical structure of various immunostimulants and their mode of action on the immune system and disease resistance of fish and shrimp and discusses the current experience and future prospects of using immunostimulants to reduce disease threats in aquaculture. Immunostimulants are already in use as helper substances (adjuvants) in fish vaccines and as additives in aquafeeds, and there is a growing interest in the aquaculture industry to make use of immunostimulants as prophylactic agents prior to situations known to represent an elevated risk of disease outbreak. Such situations include transport and handl...