Different cold tolerances among three strains of large yellow croaker: related to antioxidant defense and energy metabolism

Abstract

Abstract The aim of this study was to compare low-temperature tolerances in different strains of large yellow croaker. Dai Qu (DQ), Min-Yue Dong (MY) and Quan Zhou (NZ) strains of large yellow croaker were subjected to cold stress (8.6°C) for 12h, 24h, 48h and 96h. Survival rate, histological observation, antioxidant and energy metabolism indicators were determined. The results showed that compared with DQ group and MY group, NZ group aggravated hepatic structure, enhanced ROS, lactate and anaerobic metabolism (PK gene expression and activity), while inhibited ATP, GSH, antioxidant enzymes (mRNA levels and activities of SOD, GPx and CAT) and aerobic metabolism enzymes (mRNA levels and activities of F-ATPase, SDH and MDH), indicating the reduction of cold tolerance in NZ group was closely correlated with the decrement of antioxidative capacity and energy metabolism efficiency. Nrf2 and AMPK gene expressions were correlated with antioxidant and energy metabolism mRNA levels, respectively, suggesting Nrf2 and AMPK might participate in the modulation of target genes during the cold-stress adaptation. In conclusion, low temperature tolerance of fish depended on the antioxidant defense and energy metabolism efficiency, which contributes to understanding the underlying mechanisms of cold adaptation in large yellow croaker.