Natural Algal Communities: A Promising Solution to Inhibit Aquaculture Pathogens

A new study by Danish researchers has revealed an innovative approach to reducing bacterial pathogens in aquaculture through the development of beneficial bacterial consortia. This groundbreaking research could significantly lessen the reliance on antibiotics in aquaculture, as well as in other applications. The study, published in Microbiology Spectrum, a journal of the American Society for Microbiology, underscores the potential of non-antibiotic strategies for disease control in aquatic farming.

The Challenge of Infectious Disease in Aquaculture

Aquaculture stands as the fastest-growing sector in food protein production, boasting a lower carbon footprint compared to many traditional animal husbandry practices. However, like other intensive agricultural systems, it faces challenges posed by infectious diseases.

These outbreaks are predominantly caused by bacterial pathogens, often treatable with antibiotics. Yet, the rising problem of antibiotic resistance has highlighted the urgent need for alternative treatment methods in the industry.

Seeking Non-Antibiotic Solutions

While vaccines represent a viable strategy for disease prevention, they do not effectively target fish larvae that lack a fully developed immune system. Consequently, the use of beneficial bacteria or probiotics is gaining traction in animal husbandry and horticulture as a means to combat these threats.

Study Methodology

The researchers aimed to identify and cultivate non-antibiotic biological control measures for aquaculture. They developed an in vitro assay to assess the anti-pathogen efficacy of mixed algal microbiomes derived from live-feed microalgae, specifically Tetraselmis suecica and Isochrysis galbana. Their hypothesis was that a combination of beneficial bacteria would exhibit a stronger anti-pathogen effect than individual strains.

“To evaluate the potential of bacterial mixtures to inhibit pathogens, we tagged the fish pathogen with a green fluorescent protein. By measuring the growth and resulting fluorescence reduction, we identified bacterial communities that could effectively suppress the pathogen,” explained Dr. Lone Gram, the study’s corresponding author and a professor at the Technical University of Denmark.

Key Findings

The study revealed that certain mixtures of bacteria could inhibit Vibrio anguillarum, a known fish pathogen. Moreover, some bacteria were only effective in combination, indicating that collaborative interactions among bacterial species enhance their pathogen-inhibiting capabilities.

“Our findings suggest that it is indeed possible to find microbial mixtures within algal microbiomes that inhibit bacterial pathogens,” Dr. Gram stated. “This research opens up opportunities for engineering microbiomes aimed at reducing pathogen prevalence in aquaculture, potentially diminishing the need for antibiotics and curtailing the spread of antibiotic-resistant bacteria.”

Conclusion

This research marks a significant advancement in sustainable aquaculture practices and highlights the importance of exploring natural solutions for pathogen management. As the pressure to reduce antibiotic use in food production grows, such studies pave the way for innovative and effective alternatives that can safeguard fish health and enhance overall production sustainability.

Materials provided by American Society for Microbiology.