Exploring salinity adaptation in teleost fish, focusing on omics perspectives on osmoregulation and gut microbiota

Teleosts are the most varied vertebrates. They inhabit various environments and are crucial to global fisheries, making them a focus of research using advanced omics approaches. These studies provide insights into the genetic factors, environmental adaptability, disease resistance, and metabolic processes, aiding aquaculture sustainability. Acclimation to salinity stress is complex, influenced by genetics and the environment. Although some species tolerate varying salinity levels, rapid shifts beyond their optimal tolerance cause stress. Euryhaline species experience stress at extreme salinities, whereas stenohaline species are sensitive to minor changes. Osmoregulation maintains homeostasis at varying salinities through acclimation in the intestine, kidney, and gills, ensuring survival in changing environments. Studies on gut microbiota and metabolomics have revealed how teleosts cope with salinity stress. This review delves into the acclimatization processes through transcriptomic, metabolomic, and gut microbiome analyses, which have shed light on the complex mechanisms that teleosts have evolved to cope with salinity stress. Transcriptomic analyses have identified key ion transport, osmoregulation, and stress response genes essential for adaptation, facilitating cellular adjustments and maintaining osmotic balance across habitats. Studies have revealed significant metabolite changes in energy production and osmolyte synthesis during stress, indicating metabolic reorganization for osmoregulation. Gut microbiota analysis highlights microbial diversity in regulating osmoregulatory functions, emphasizing microbiota’s role in resilience. Although research on interactions between salinity, growth conditions, and gut microbiota in teleosts is limited, findings suggest a vital relationship that warrants further study. Understanding these mechanisms is essential for improving fish health and enabling sustainable aquaculture management under environmental fluctuations.