Actinomycetes as a promising candidate bacterial group for the health management of aquaculture systems: A review.

Abstract

Aquaculture is one of the most important economic activities in the world. However,the intensification of culture practices resulted in the emergence of various diseasescaused by microorganisms and non-infectious diseases caused mainly by the deterio-ration of water quality. Several prophylactic and treatment options have beenexploited over the years to tackle the disease problem in aquaculture. Previously,antibiotics have been used indiscriminately for treating many fish diseases whichresulted in the emergence of antimicrobial resistance. To overcome the failure ofexisting management strategies, innovative antimicrobial drug research is crucial andactinomycetes have proven to be trustworthy sources of new antimicrobial chemicalsand are one of the most economically and biotechnologically important bacteria withmultitude of functions. This review updates and highlights the role of actinomycetesin encouraging sustainable aquaculture practices and identifies opportunities foradditional research and development. Many genera of actinomycetes were found toenhance the growth and survival of cultured species by producing many nutritionalfactors. They also improve the water quality of culture systems by the production ofhydrolytic enzymes. Actinomycetes were found to improve the immunity of aquaticorganisms by augmenting many immune parameters and making them more resistantto infection. Many actinomycetes have been discovered to produce antagonistic sub-stances and exhibited antibacterial, antiviral, antibiofilm and anti-quorum sensingactivities. Probiotic potential of many actinomycetes has been widely explored. Eventhough actinomycetes have been widely used in aquaculture for multi purposes, theexact mechanism of action of these bacterial groups is poorly understood and novelbiotechnological tools can be used for unravelling this.