Commercial production of Florida pompano (Trachinotus carolinus) larvae at low salinity induces variable changes in whole-larvae microbial diversity, gene expression, and gill histopathology

Introduction Salinity presents economic and technical challenges in land-based recirculating aquaculture systems (RAS) the U.S. warm water marine finfish industry. Many studies have shown euryhaline fish reared at salinities closer to their iso-osmotic salinity can yield enhanced production performance as well potential reduced costs farms. However, there is for osmotic stress larvae negatively impact microbiome innate immune system. Florida pompano (Trachinotus carolinus) a popular sportfish has been targeted RAS due its impressive market value capacity. This study investigated impacts of rearing salinity. Materials methods Larvae were cultured 10, 20, 30 ppt triplicates, samples collected histopathology, microbiome, whole transcriptomics analysis every three days from hatching until time weaning (24 post hatch [DPH]). Water also taken on other larval sampling day. Discussion These changes driven more by metamorphosis, causing an increase expression antioxidant genes (cat, gss, gsto1, scara3) than presence potentially pathogenic genera, which failed induce response (low or unchanged downstream elements NOD1 TLR5 pathways). findings provide baseline information low tolerance larviculture during early developmental stages. In addition, we minimal effects system 10 ppt. work important implications health management be used refine direct future research regarding improving commercial species