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 diseases caused by microorganisms and non-infectious diseases caused mainly by the deterioration of water quality. Several prophylactic and treatment options have been exploited over the years to tackle the disease problem in aquaculture. Previously, antibiotics have been used indiscriminately for treating many fish diseases which resulted in the emergence of antimicrobial resistance. To overcome the failure of existing management strategies, innovative antimicrobial drug research is crucial and actinomycetes have proven to be trustworthy sources of new antimicrobial chemicals and are one of the most economically and biotechnologically important bacteria with multitude of functions. This review updates and highlights the role of actinomycetes in encouraging sustainable aquaculture practices and identifies opportunities for additional research and development. Many genera of actinomycetes were found to enhance the growth and survival of cultured species by producing many nutritional factors. They also improve the water quality of culture systems by the production of hydrolytic enzymes. Actinomycetes were found to improve the immunity of aquatic organisms by augmenting many immune parameters and making them more resistant to infection. Many actinomycetes have been discovered to produce antagonistic substances and exhibited antibacterial, antiviral, antibiofilm and anti-quorum sensing activities. Probiotic potential of many actinomycetes has been widely explored. Even though actinomycetes have been widely used in aquaculture for multi purposes, the exact mechanism of action of these bacterial groups is poorly understood and novel biotechnological tools can be used for unravelling this.