Impacts of Probiotics on Microbial Populations in Aquaculture Systems

Aquaculture, as a key industry providing the growing global population with animal protein, has observed massive growth in recent years. This growth experienced is a result of the several advances made to improve aquaculture worldwide, including the use of probiotics. Probiotics have been investigated and proven to be beneficial in aquaculture; yet their accurate and effective distribution still requires critical considerations. As live microorganisms, the inclusion of probiotics into aquaculture environments undisputably impacts their microbial ecology. Understanding probiotics’ impact on aquatic systems’ microbial community is crucial and necessary in determining their safe dosage and use. Little attention has been paid to how probiotics affect the microbial communities of aquaculture systems; only a handful of studies have examined their influence on these communities’ structure. This article, therefore, synthesizes the limited research that has examined how probiotics alter the abundance of some key bacterial groups in aquaculture systems, such as heterotrophs, beneficial species, pathogens, nitrifiers and denitrifiers, bioremediators, and anoxygenic phototrophs, to highlight this almost overlooked issue. Also, the role of probiotics in gene transfer among bacterial communities is discussed in this review article. By stimulating beneficial microbial populations while suppressing pathogenic ones, probiotics appear to reshape the microbial communities in aquaculture systems, providing a powerful lever for systemic improvements. However, the responses of environmental microbial communities to these interventions have not been fully studied, making expanded, targeted research imperative.