Natural Algal Communities can reduce antibiotic use in aquaculture

The American Society for Microbiology (ASM) journal, Microbiology Spectrum, has published a new study by Danish researchers demonstrating how the development of a bacterial consortium, like natural algal communities, can inhibit bacterial pathogens in aquaculture.

The rise of antibiotic-resistant bacteria is prompting more researchers to focus on developing non-antibiotic biological options for the control and prevention of diseases in aquaculture.

Although vaccines can be a good preventive measure, they typically do not work on fish larvae that do not have a developed immune system. Instead, the use of beneficial bacteria or probiotics to combat pathogens is becoming increasingly common, as confirmed by ASM.

The potential of Natural Algal Communities

Natural Algal Communities are groups of algae that develop spontaneously in a natural environment. They can include both microalgae and macroalgae and serve as the foundation of the food chain for many aquatic organisms.

First, an in vitro assay was conducted to evaluate the anti-pathogen efficacy of mixed algal microbiomes from the live-feed microalgae Tetraselmis suecica and Isochrysis galbana.

The findings demonstrate how bacterial mixtures inhibit Vibrio anguillarum, a fish pathogen, and then isolate pure bacterial cultures. Additionally, the researchers confirmed that these bacteria only inhibited the fish pathogen when combined.

"We have shown that it is possible in microbiomes to find mixtures of bacteria that can inhibit the pathogen. Thus paving the way for engineering microbiomes that can inhibit bacterial pathogens and reduce the need for the use of antibiotics. We can then reduce the spread of antibiotic-resistant bacteria," said corresponding study author Lone Gram, Ph.D., professor in the Department of Biotechnology and Biomedicine, Technical University of Denmark.