Bacteriophages for aquaculture: Are they beneficial or inimical

Abstract

World fisheries production is projected at 164 million tonnes in 2020, and a major increase in the quantity of fish produced is expected to originate from aquaculture. Diseases represent a severe threat to aquaculture productivity and natural/organic strategies to combat infectious diseases are gaining new ground to address the issues of antibiotic resistance of bacteria and issues related to antibiotic residues in aquatic food animals. Phage therapy is currently considered as a viable alternative to antibiotics for treatment of bacterial infections in aquaculture systems. A cocktail of lytic phages and a synergistic combination of phages and other antimicrobials are viable options to control bacterial infections and at the same time evade phage resistance. However, lysogenic phages have the ability to transform non-virulent bacterial strains in to virulent strains which may cripple aquatic food production and also threaten food safety. The review focuses on the roles of bacteriophages and their implications for aquatic food production and food safety. • Phage therapy is considered as a viable alternative to antibiotics for treatment of bacterial infections in aquaculture. • Cocktail of lytic phages is a better option to control bacterial infections and evade phage resistance. • Lysogenic phages transform non-virulent bacteria in to virulent strains which may threaten food production and food safety. • Food safety regulations are needed for use of bacteriophages to exclude possible spread of undesired virulent genes.