One Function, Many Faces: Functional Convergence in the Gut Microbiomes of European Marine and Freshwater Fish...

Area of Science:

• Aquatic microbiology
• Fish immunology
• Microbiome research

Background:

• Intestinal microbiota composition is influenced by diet, environment, and host genetics.
• Assessing and monitoring microbiome-host interactions is crucial for aquaculture.
• Understanding these interactions aids in developing sustainable aquaculture practices.

Purpose of the Study:

• To analyze the taxonomic structure and functional potential of intestinal microbiota in European sea bass and rainbow trout.
• To identify core microbiota and their role in community organization.
• To explore functional contributions of the core microbiota to host metabolism.

Main Methods:

• Taxonomic and functional analysis of intestinal microbiota.
• Bayesian network analysis to understand microbial community interactions.
• Comparative analysis of microbial biomarkers across different fish species and environments.

Main Results:

• Identified core microbiota (40 taxa in sea bass, 20 in trout) playing a central role in community organization.
• Core microbiota exhibited predominantly positive connections within the microbial community.
• Core-associated bacteria accounted for the majority of predicted metabolic pathways, especially in carbohydrate, amino acid, and vitamin metabolism.
• Distinct microbial biomarkers were identified for saltwater and freshwater species.

Conclusions:

• Integrating taxonomic, functional, and network-based approaches provides practical tools for monitoring intestinal health and welfare in aquaculture.
• The findings support the development of sustainable aquaculture production strategies.
• Specific microbial genera can serve as biomarkers for different ecological phenotypes in farmed fish.