Identification of key overlapping DEGs and molecular pathways under multiple stressors in the liver of Nile tilapia (Oreochromis niloticus)

The identification of key genes and molecular pathways that are involved in the response to stressors is crucial for controlling stress in fish and sustainable aquaculture. Environmental stressors can induce stress responses in aquatic animals, resulting in compromised immune function, inhibited growth, and increased mortality rates. mRNA-seq analysis provides a powerful tool to identify key genes and pathways associated with stress response. In the present study, mRNA-seq analysis was employed to identify key overlapping differentially expressed genes (DEGs) and molecular pathways under salinity, nitrite, copper, and pH stress in the liver of Nile tilapia (Oreochromis niloticus). The pathways associated with the immune response, oxygen transport, homeostasis, and oxidative stress were enriched across all stressors. The top KEGG pathways were complement and coagulation cascades, PPAR signaling pathway, and cardiac muscle contraction. The top GO enrichment terms were oxidoreductase activity, aerobic respiration, endopeptidase inhibitor activity, endopeptidase regulator activity, heme binding, and iron ion binding. The complement genes (C3, C4, C5, factor B, and factor H), alpha-2-macroglobulin (A2M), hemoglobin subunit epsilon (HBE), hemoglobin subunit alpha (HBA), coagulation factor genes (XI and X) and the cytochrome c oxidase (COX) gene family (cox1, cox2, cox3, cytochrome P450) were identified as key shared genes across multiple stressors. The discovery of these genes and molecular pathways provided a better understanding of the molecular mechanism underlying the stress response in Nile tilapia. The results of the present study can facilitate the development of stress management strategies in Nile tilapia.