AQUAculture infrastructures for EXCELlence in European fish research 3.0

Infectious diseases are a major threat to aquaculture, particularly impacting commercially valuable species such as oysters. Diseases lead to significant economic losses and are a primary limiting factor for aquaculture growth. This problem is also prevalent in Pacific oyster (Crassostrea gigas) production, where both larvae and adult oysters are susceptible to various diseases; in this project, we focussed on bacterial diseases.

Research on this topic is crucial due to the substantial impact bacterial diseases have on oyster aquaculture. Current treatment methods are limited and often involve antibiotics, which can have negative environmental effects and contribute to antibiotic resistance. Therefore, developing alternative solutions, such as probiotics, is essential for sustainable aquaculture practices.

The underlying research aimed to explore antibiotic-free tools to improve the health and welfare of oyster aquaculture. The main objectives were to determine the protective effects of next-generation probiotics (NGP) against bacterial pathogens in oyster larvae and adults and, later on, investigate the mechanisms of action through molecular techniques. This study showed that some NGP tests lowered oyster mortality in challenge tests, a promising result that could ameliorate the morality in oyster aquaculture. More research will be needed in the future to optimize these NGP applications, understand their long-term effects, and explore their application across different aquaculture species and environmental conditions.