Abstract:To investigate the effects of low-temperature stress on the antioxidant and non-specific immune capacity of crayfish (Procambarus clarkii), we collected hepatopancreas, gills and haemolymph at 4 temperature levels (control: 23 ℃, experimental group: 9 ℃, 5 ℃, 1 ℃), then measured antioxidant and immune-related enzyme activities and gene expression. The results of antioxidant and immunoenzymatic activities showed a gradual increase in total antioxidant capacity (T-AOC) activity in hepatopancreas and haemolymph of P. clarkii under low temperature stress. The trend of increasing and then decreasing activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), acid phosphatase (ACP) and alkaline phosphatase (AKP) was observed in hepatopancreas and haemolymph. Both malondialdehyde (MDA) contents increased gradually, peaking at 1 ℃. Catalase (CAT) decreased gradually in the hepatopancreas with an increase followed by a decrease in the haemolymph. Gene expression results showed that mRNA expression of SOD, CAT, and Crustin genes in gills and hepatopancreas of P. clarkii increased and then decreased with decreasing temperatures under low-temperature stress,and the heat shock protein 70 (HSP70) gene mRNA expression does not change significantly in gills with an increase followed by a decrease in hepatopancreas. In summary, oxidative stress occurred in P. clarkii under low-temperature stress, and the antioxidant and immune system responded to low-temperature oxidative damage by increasing the activity of antioxidant and immune enzymes and inducing the high expression of antioxidant and immune genes, to protect cellular activity and maintain normal life activities. The results of this study provide a theoretical basis for the selection and breeding of low temperature resistant strains of P. clarkii under the integrated rice-crayfish aquaculture model.