Functional Aquafeeds for Climate-Resilient Finfish Culture: A PRISMA-Guided Systematic Evidence Map of Nutritional Strategies for Thermal-Stress Tolerance, Immunity and Metabolic Homeostasis

Thermal variability associated with climate change is an increasing constraint for finfish aquaculture because water temperature directly affects feed intake, nutrient utilization, endocrine stress responses, oxidative balance, immunity, intestinal integrity and survival. The literature search was conducted without a lower publication-year restriction through 5 July 2026. Database and citation-linked searches identified 386 candidate records, of which 274 remained after duplicate removal; 71 full-text articles were assessed; and 28 peer-reviewed primary feeding studies with publicly available final versions of record were retained for qualitative evidence mapping. The eligible studies were published between 2012 and 2026, with 2012 representing the earliest eligible publication rather than a prespecified starting year. Functional aquafeeds have therefore emerged as promising nutritional tools for supporting physiological resilience under heat, cold and sub-optimal temperature conditions. This review developed a PRISMA-guided systematic evidence map of dietary functional-aquafeed strategies evaluated for thermal-stress tolerance, immune regulation, antioxidant defense and metabolic homeostasis in cultured finfish. The main synthesis emphasizes studies with direct dietary thermal-stress interventions and extractable mechanistic outcomes, including sodium butyrate, organic selenium, selenium nanoparticles with riboflavin, astaxanthin, Bacillus spp., propolis, bay laurel essential oil, Spirulina-based strategies and essential oils. Overall, the available evidence suggests that selected functional aquafeeds may support thermal-stress resilience through coordinated improvements in antioxidant capacity, reduced oxidative damage, modulation of cortisol/glucose and heat-shock responses, enhancement of innate and mucosal immunity, improved intestinal or tissue condition and stabilization of metabolic indicators. The most biologically coherent translational patterns were observed when dietary interventions improved multiple response domains simultaneously rather than a single biomarker. However, such cross-domain improvement was interpreted as mechanistic and translational support rather than as an independent indicator of evidence confidence, which depended primarily on independent replication, consistency of response direction and methodological quality. Nevertheless, the current evidence remains uneven across species, stress models, life stages and outcome domains, with limited data for marine carnivores, repeated temperature fluctuation, post-stress recovery, disease challenge and multiomics integration. Therefore, the findings should be interpreted as a structured evidence map rather than universal formulation guidance. Future studies should use standardized thermal-challenge protocols, dose–response designs, clear tank-level experimental-unit reporting and integrated biomarker panels to support practical development of climate-resilient functional aquafeeds.