Mineral-microbiota interactions in aquaculture: implications for fish gut health and nutrition.

Dietary minerals and gut microbiota engage in a dynamic, bidirectional relationship that shapes the health, immune competence, and productive performance of farmed fish and shrimp. This review explores the bidirectional interactions between mineral supplementation and microbial communities within the gastrointestinal tract of farmed fish and examines the effects of individual and combined mineral supplementation including iron, zinc, magnesium, selenium, manganese, and copper in inorganic, organic, and nanoparticle forms on the intestinal microbiota and histomorphology of farmed aquatic species. Minerals serve essential physiological roles while simultaneously modulating microbial diversity, composition, and metabolic activity; conversely, the gut microbiota influences mineral bioavailability and absorption through enzymatic transformations and competitive uptake. Studies conducted on yellow catfish, largemouth bass, golden pompano, grouper, Nile tilapia, Chinese tongue sole, Pacific white shrimp, channel catfish, zebrafish, and Oriental river prawn were comprehensively examined. Findings indicate that organic and nanoparticle mineral forms generally exhibit higher bioavailability and more favorable effects on intestinal health compared to conventional inorganic sources, with partial substitution strategies (e.g., ~ 50% organic mineral replacement) yielding optimal outcomes in combined formulations. Optimized mineral supplementation was further associated with enrichment of beneficial microbiota, enhanced mucosal barrier integrity through goblet cell proliferation, and reinforcement of innate immune responses, collectively supporting nutrient assimilation, growth performance, and disease resistance. However, the reviewed studies share critical limitations: species diversity was narrow, experimental durations were short (8–80 days), no trial encompassed a full reproductive cycle, and the mechanisms underlying mineral–microbiota crosstalk remain incompletely understood. Synergistic or antagonistic interactions among Zn, Cu, Mn, Fe, and Se are inadequately characterized, and dose optimization specific to species, age, and physiological status has not been achieved. Future research should incorporate long-term and multigenerational designs, metagenomic and metabolomic analyses, comparative multi-mineral trials, and the integration of microbiome-based diagnostics to tailor mineral interventions, alongside validation under commercial aquaculture conditions and ecotoxicological assessment of nanoparticles in aquatic environments.