Effects of β-glucan on ROS production and energy metabolism in yellow croaker (Pseudosciaena crocea) under acute hypoxic stress.

The aim of the present study was to evaluate the effect of β-glucan on acute hypoxia-induced oxidative stress and the changes in energy metabolism by determining ROS production, activities and mRNA levels of energy metabolism enzyme (PK, F-ATPase, SDH and MDH), and in gene expression of HIF-1α in the liver of large yellow croaker. Fish were injected with β-glucan at a dose of 0 or 5 mg kg(-1) body weight on 6, 4 and 2 days before exposed to 1.5 and 7.0 mg DO L(-1) for 48 h. The results showed that β-glucan enhanced survival rate and reduced ROS during the lethal hypoxic stress, indicating that β-glucan could ameliorate hypoxia-induced oxidative stress. Obtained results also showed that β-glucan could up-regulate activities and mRNA levels of PK, demonstrating that β-glucan increased anaerobic glycolysis capacity. Furthermore, a coordinated transcriptional regulation of energy metabolism enzyme genes was observed, suggesting that HIF-1α is required for regulating these genes. In conclusion, β-glucan could alleviate cute hypoxia-induced oxidative stress in large yellow croker by enhancing anaerobic glycolysis capacity, emphasizing a central role of transcription factor HIF-1α in the process.