Bioprospecting gastrointestinal microflora of common fishes for disease control in aquaculture

Abstract

The aquaculture industry faces many challenges related to diseases, which leads to serious economic losses worldwide. Massive use of antimicrobial agents encourages the natural emergence of antibiotic-resistant bacteria. As such, there is an urgent demand on the use of beneficial bacteria as a better strategy for disease control. Commercially available probiotics are mostly sourced from terrestrial origins. However, their extensive usage in fish farming could cause unexpected adverse effects to the aquaculture species. Therefore, there is an immediate need to select probiotics originating from fishes. This chapter discusses the importance of beneficial bacteria in disease prevention and management. The role of probiotic in aquaculture is explicitly elucidated in this section. The complex microbial profile and dynamics of the microflora in the fish microbiota is also discussed here, particularly with the aid of metagenomics. Bioprospecting of beneficial microflora as probiotics is described based on the various rigorous tests (e.g. antagonistic tests, antibiotic susceptibility and haemolytic assays) performed. Other aspects examined to select for beneficial bacteria include colonization and proliferation capability, host immunomodulation, stimulation of enzymatic production and amenability to biotransformation for efficient delivery. All these propel the interest in understanding gastrointestinal microflora for probiotic development to control diseases in aquaculture.