Impact of predation on the bacterial community structure of Mediterranean mussels during depuration

TL;DR

This study explores how predation by bacteria affects the microbiome of Mediterranean mussels during depuration, a process used to clean them before consumption.

Contribution

The study introduces the use of predatory bacteria as a potential biocontrol strategy to reduce Vibrio spp. in mussels during depuration.

Findings

Depuration significantly altered the mussel microbiota, reducing its resilience.

Adding predatory bacteria disturbed the mussel microbiome during depuration.

The effect of bacterial predation on the microbiome is not easily predictable.

Abstract

The Mediterranean mussel (Mytilus galloprovincialis) is the most valuable shellfish farmed and consumed in the Western Mediterranean. Like any other filter-feeding organism, mussels are exposed to a wide range of microorganisms. Before consumption, bivalves are subject to depuration to purge the gastrointestinal content, thus minimizing the risk of pathogens’ circulation. Over time, this strategy revealed several shortcomings, most notably concerning Vibrio spp. In this study, the potential use of autochthonous predatory bacteria as a biocontrol strategy to mitigate Vibrio spp. overgrowth in mussels during depuration was evaluated. Moreover, a polyphasic approach based on conventional and culture-independent strategies was used to assess the impact of predation and of depuration on the mussel microbiome during controlled depuration studies. The depuration greatly impacted the bivalve microbiota, jeopardizing its innate resilience. Moreover, the addition of a bacterial predator strain to mussels resulted in the disturbance of the microbiome. Therefore, even though the biotechnological application of bacterial predation in this context may appear promising when monitored by culture-dependent methods, the effect on the mollusks’ microbiome does not seem to be easily predictable, above all when mussels are subject to depuration after the harvest.

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