Genomic resources for immunology and disease of salmonid and non-salmonid fish

Abstract

The enormous development of aquaculture has increased the interest in infectious diseases of cultured fish, due to the economic losses caused by them. Although at present there are successful vaccines against bacteria, therapeutic treatments for viral diseases have yet to be established, in part due to the lack of information regarding the defense mechanisms triggered during infections. Fish have an innate and an acquired immune system, the former is the first line of defense and therefore an important protection against pathogens. The reason is the relatively inefficiency of the acquired immune response of fish in comparison with the unspecific response, given the evolutionary status and poikilothermic nature of these animals. In spite of this, not many genes related to the innate immune system in fish have been cloned. However, this number has increased lately owing to the recent advances in the study of simultaneously gene expression (Expression Sequence Tags, ESTs, and microarrays). The use of these techniques (genomic and proteomic) together with functional studies of gene expression in vivo and in vitro will favour future aquaculture development. In this sense, many genes and regulatory pathways of biological processes in general and defense mechanisms in particular could be identified and characterized. This knowledge will allow not only to determine the molecular basis of these responses, but can also be used in the improvement of cultured species via effective fight strategies against pathogens, new vaccine design and genetic selection of disease resistant species. In this chapter we review the application of these genomic techniques used to study immune response and disease resistance of mainly non salmonid fish.