Hypoxia alters glucose and lipid metabolisms in golden pompano (Trachinotus blochii)

Sufficient dissolved oxygen (DO) is essential for most teleosts. However, high-density aquaculture and fluctuating environmental factors can result in hypoxic stress in golden pompano (Trachinotus blochii). In this study, physiological, biochemical and transcript indicators of metabolism and apoptosis were investigated in T. blochii under hypoxic conditions (1.9 ± 0.2 mg/L) for 12 h. Increases in the content of lactic acid (LD) and the activity of lactate dehydrogenase (LDH), pyruvic acid (PA), phosphofructokinase (PFKA), and hexokinase (HK) suggested the enhancement of anaerobic glycolysis under hypoxic stress. Furthermore, significant increases in triglycerides (TGs) and lipoprotein lipase (LPL) in the liver under hypoxic stress for 6 h and a high level of carnitine palmitoyltransferase-1 (CPT-1) under hypoxic stress for 12 h indicated activation of lipid utilization. Additionally, glycolysis/gluconeogenesis, sphingolipid metabolism, pentose phosphate, HIF-1, and p53 signaling pathways were activated in response to hypoxia. Eleven DEGs involved in these pathways were identified. The relative expressions of HIF-1α (Hypoxia Inducible Factor 1 Subunit Alpha), PGM (phosphoglucomutase), PFKA (6-phosphofructokinase 1), HK (hexokinase), SMPD3 (sphingomyelin phosphodiesterase 3), SPT (serine palmitoyltransferase), and EPO (erythropoietin) were up-regulated under hypoxic conditions. Additionally, the relative expressions of RGN (gluconolactonase), CCNG2 (cyclin G2), CERS1 (sphingoid base N-stearoyltransferase 1), and IGFBP3 (insulin-like growth factor-binding protein 3) were down-regulated. This research reveals metabolic changes and cell apoptosis activation in T. blochii under hypoxic conditions, providing new insight into metabolic responses to hypoxia in teleosts.