Exploring the fish microbiome in Mediterranean species: drivers, dynamics and relationships with fish health, food safety and environmental sustainability

Fish microbiome plays a crucial role in host health, influencing growth, immune response, and disease resistance. Understanding the fish microbiome from different perspectives is of primary importance to develop improved aquaculture practices, to provide safer food from the sea and to manage fish resources efficiently. In this Thesis, fish microbiome of some of the most relevant (farmed and wild) fish species at the Mediterranean level has been conducted, to address the following scientific questions: What are the changes in microbiome composition occurring throughout different life developmental stages of farmed fish? Which are the main drivers of these changes? Is antimicrobial resistance an issue in aquaculture, and how does it change along the production cycle of farmed fish? Can fish microbiome be modulated through dietary intervention strategies? Can novel dietary ingredients (including those from new, sustainable sources) influence fish microbiome and overall health status and productivity? How do wild and farmed fish microbiomes differ? Are there microorganisms which are shared between farmed and wild fish? How research on wild fish microbiome can potentially support fish stock management as well as future new applications of fish farming? This thesis is organized in different Chapters that aim at addressing such questions, and focuses on the microbiome of some of the most commercially and ecologically relevant fish species at the Mediterranean Sea level, i.e., Mediterranean gilthead sea bream (Sparus aurata) and common sole (Solea solea).