Use of microalgae and bacteria to enhance protection of gnotobiotic Artemia against different pathogens

The present study investigates the use of microalgae, probiotic and dead bacteria in gnotobiotic Artemia to overcome the virulence of two pathogenic bacterial strains: Vibrio campbellii and Vibrio proteolyticus. For that purpose, two strains of the microalga Dunaliella tertiolecta (a medium- and a good-quality microalga) and two beneficial bacteria, selected from previous well-performing Artemia cultures, were provided to the brine shrimp cultured under gnotobiotic conditions. The daily supplementation with D. tertiolecta conferred full protection to Artemia towards both vibrios and was apparently more efficient and stable than the use of probiotics and dead bacteria. Only when Artemia were cultured in sub-optimal conditions with microalgae (but not when fed ad libitum), the addition of probiotic bacteria was able to partially protect the animals against both pathogens. The contribution of dead bacteria to the protection of Artemia against both pathogens was more pronounced in animals cultured with poor-quality feeds.