Finfish Microbiota and Direct-Fed Microbial Applications in Aquaculture

Abstract

Globally, the production of food fish has continued to grow at a pace unrivaled by other animal livestock production sectors, with over half of the world’s seafood now coming from aquaculture. As aquaculture continues to grow, managing finfish health and nutrition in an economically and environmentally sustainable manner is imperative but has become more difficult because of multifaceted pressures facing the industry. Mounting research evidence on the interplay between finfish and the microbes that inhabit their nares, skin, and gills and especially their gut suggests that microbiota play important roles in the physiological processes of fish. Here, we review the current status of microbiota research in finfish and the application of direct-fed microbial (DFM) strategies to improve finfish production performance in aquaculture. While many DFMs, including probiotic and synbiotic supplements, have been tested in aquaculture with varied, though often positive, outcomes, current implementation remains largely relegated to the research setting. However, we expect that the continued and increasing pressure to eliminate antibiotic use and increase reliance on alternative diet formulations will make DFMs an integral part of sustainable large-scale aquaculture moving forward, though successful implementation will hinge on some key factors and considerations, as will be further addressed in this chapter.