Gut Microbiota as a Driver of Fish Phenotype and Performance: Mechanisms and Host–Microbe Interactions

Fish biology and aquaculture research are increasingly recognizing the pivotal role of gut microbiota in modulating host phenotype and overall performance. Recent evidence highlights that these complex microbial ecosystems not only facilitate nutrient absorption and bolster immune function, but also intersect with metabolic, neuroendocrine, and developmental pathways vital to growth, stress resilience, and swimming performance. While significant strides have been made in describing distinct microbial community structures across various fish species and environments, the field faces ongoing debates regarding causality, functional mechanisms, and the multidimensional nature of host-microbiota interactions. Key studies have illuminated the influence of diet, environment, and host genetics on microbiome composition, and have started to uncover how specific microbes or metabolites affect central physiologic and behavioral outcomes. However, a mechanistic and context-sensitive understanding of how microbial communities drive—or respond to—changes in fish phenotype and performance remains incomplete, limiting progress toward predictive and actionable interventions.This Research Topic aims to deepen our mechanistic and integrative knowledge of the ways in which gut microbiota actively shape fish phenotype and performance across life stages, species, and ecological settings. The overarching goal is to move beyond correlative observations by developing and applying approaches that establish causal relationships and unravel the functional basis of host–microbe interactions. We particularly encourage interdisciplinary work that combines microbiology, immunology, physiology, nutrition, and systems biology, and that seeks to clarify how gut microorganisms and their metabolites mediate adaptation, resilience, and disease resistance in fish—both in natural and aquaculture systems.This Research Topic will focus on delineating microbiota-driven mechanisms within well-defined boundaries, emphasizing studies that strive for mechanistic clarity and lend themselves to translation in diverse aquatic contexts. We welcome all article types accepted by the journal including original research, reviews, perspectives, and methods exploring, but not limited to, the following themes:o Microbiota-mediated regulation of growth, metabolic efficiency, and nutrient utilizationo Modulation of mucosal immunity, inflammation, and pathogen resistance by gut microbeso Roles of microbial metabolites and signalling molecules in shaping host physiologyo Microbiota influences on stress physiology, thermal and hypoxia adaptation, and welfareo Behavioral and neuroendocrine effects, including the microbiota–gut–brain axis in fisho Assembly and transmission of gut communities during development and early lifeo Impacts of diet, feed additives, functional foods, and microbial therapeutics on host–microbiome dynamicso Consequences of antibiotics, pollutants, environmental stressors, and farming practiceso Innovations in experimental models, multi-omics integration, metabolomics, imaging, and causal inference. Topic editors: Carmen Navarro-Guillén, Gabriela N. Tenea, Prof. M Y Sreenivasa, Fangchao Song, Federica Montesanto Source: https://www.frontiersin.org/research-topics/77787/gut-microbiota-as-a-driver-of-fish-phenotype-and-performance-mechanisms-and-host-microbe-interactions