The use of antibiotics and therapeutics for Nile tilapia has increased along with its increased production and intensification. Probiotics have been studied as an alternative to the excessive use of antibiotics in fish diets. Studies have demonstrated that dietary Bacillus probiotic inclusion promotes faster growth and disease resistance in farmed fish species. Despite advances in research, there is still uncertainty about the mechanisms controlling the immune response of fish. In this review, we summarize and discuss recent research on the immune responses of Nile tilapia to Bacillus probiotics. Through the use of immunological information including phagocytosis, lysozyme activity, respiratory activity, antioxidant proteins, complement activity, and immune-related gene expression, researchers hope to develop effective strategies for successfully using Bacillus probiotics in Oreochromis niloticus farming.

Recently, China has become a hotspot for farming golden pompano (Trachinotus ovatus), a commercially valuable marine fish. The genetic mechanisms underlying ovarian development, particularly those regulated by insulin-like growth factors (IGFs), remain poorly understood. Existing research on T. ovatus has focused primarily on growth metrics, developmental stages, and immune responses, leaving a critical gap in knowledge regarding the hepatic regulatory pathways activated by IGFs. In this study, differentially expressed genes (DEGs) were detected through RNA sequencing (RNA-Seq) and associated pathways in response to IGF treatment. Comparisons between the IGF1, IGF2, and IGF3 treated groups and the control revealed 113 (46 upregulated, 67 downregulated), 637 (567 upregulated, 70 downregulated), and 587 DEGs (273 upregulated, 314 downregulated), respectively. KEGG enrichment analysis highlighted key pathways that may be linked to ovarian growth and development, including biotin metabolism, biosynthesis of amino acids, drug-cytochrome p450 pathways, MAPK signaling, estrogen signaling pathways, ECM receptor interaction, steroid biosynthesis, and ovarian steroidogenesis. These findings advance our understanding of hepatic metabolic regulation in golden pompano via the IGF system and provide actionable insights for optimizing aquaculture practices and selective breeding programs for this species.