Microbial ecology of the gastrointestinal tract of fish and the potential application of probiotics and prebiotics in finfish aquaculture

Abstract

World aquaculture is the fastest growing food-producing sector in the world. Globally, aquaculture is expanding into new directions, intensifying and diversifying. With increasing demand for environment friendly aquaculture, the use of alternatives of antibiotic growth promoters in fish nutrition is now widely accepted. Science-based knowledge on probiotics and prebiotics has increased in recent years. No doubt exist that in the last decade we have greatly expanded our knowledge about pro- and prebiotics as important functional ingredients in finfish aquaculture. They have numerous beneficial effects: improved activity of gastro-intestinal microbiota and enhanced immune status, disease resistance, survival, feed utilization and growth performance. As natural products pro- and prebiotics have much potential to increase the efficiency and sustainability of aquacultural production. Therefore, comprehensive research to more fully characterize the intestinal microbiota of prominent fish species, mechanisms of action of pro- and prebiotics, and their effects on intestinal ecosystem, immunity, fish health and performance is warranted. All pro- and prebiotics must be evaluated for their safety before being used in fish nutrition. Also, there is need for establishing dose-response relationships. The application of up to date molecular procedures to study of the gut microbiota as well as the development and validation of research methods, <em>in vitro</em>, <em>ex vivo</em> and <em>in vivo</em> models, have provided important information to understand the mechanisms of action behind the effects. This review summarizes and evaluates current knowledge of microbial ecology of the gastrointestinal tract of fish as well as the potential application and challenges of pro- and prebiotics in finfish aquaculture.