Abstract:In this study, we aimed to explore the effects of low-temperature dormancy on survival rate, apparent traits, immune function, antioxidant capacity, and muscle quality of Procambarus clarkii, providing a reference for off-season listing of P. clarkii. Experimental animals included P. clarkii with a body weight of (17.98±0.83) g and a body length of (6.55±0.07) cm. Initially, P. clarkii were cooled from 25 ℃ at a rate of 5 ℃/h to determine the critical dormancy and death temperatures. Subsequently, cooling and heating rates were set at 2 ℃/h, 3 ℃/h, 4 ℃/h, and 5 ℃/h, with different dormancy temperatures applied to P. clarkii. Optimal dormancy conditions were determined based on different cooling rates, dormancy temperatures, and survival rates of P. clarkii. Changes in apparent traits, serum immune and antioxidant indicators, and muscle quality of P. clarkii under optimal dormancy conditions were then assessed. The critical dormancy temperature for P. clarkii was 7 ℃, and the critical death temperature was 0 ℃. The highest survival rates were observed at a cooling rate of 2 ℃/h, 5 ℃ dormancy for 60 days, and a warming rate of 2 ℃/h, with survival rates of (97.50±1.12)%, (60.50±2.02)%, and (98.33±1.05)%, respectively. Therefore, the optimal dormancy conditions were a cooling rate of 2 ℃/h, 5 ℃ dormancy, and a warming rate of 2 ℃/h. No significant differences in body weight, body length, condition factor (CF), hepatopancreas weight, or hepatopancreas index (HSI) were observed after 60 days of dormancy compared with 0 days under optimal conditions. Similarly, no significant differences in ACP activity, SOD activity, and MDA content were observed in the serum of P. clarkii after 15, 30, 45, and 60 days of dormancy (P>0.05). AKP activity at 30 days of dormancy was significantly higher than that at other time points (P<0.05), while AKP activity at 60 days was significantly lower (P<0.05). After 60 days of dormancy, muscle hardness and recovery of P. clarkii were significantly reduced (P<0.05), and cohesion was significantly increased (P<0.05); changes in muscle umami amino acids alanine, aspartic acid, glutamic acid, and glycine were not significant (P>0.05). In conclusion, the cooling rate of 2 ℃/h, dormancy at 5 ℃, and heating rate of 2 ℃/h were optimal low-temperature dormancy survival conditions. After 60 days of dormancy under these optimal conditions, the apparent traits of P. clarkii did not change significantly. However, with prolonged dormancy, immune and antioxidant regulatory functions weakened, and survival rates decreased. Although low-temperature dormancy caused some changes in the physical and chemical properties of P. clarkii muscle, muscle flavor did not change significantly.