Effects of temperature on the growth parameters, hepatopancreas structures, antioxidant ability, and non-specific immunity of the crayfish, Cherax destructor

Cherax destructor, a native Australian freshwater crayfish, has been extensively studied for its aquaculture potential, but its growth and immune responses at different temperatures remain unclear. In this study, after 8 weeks of culture at 10 °C, 15 °C, 20 °C, 25 °C, and 30 °C, the effects of temperature on growth parameters, hepatopancreas histology, antioxidant, and immune indexes in C. destructor were evaluated. The results revealed that the specific growth rate was decreased in the 10 °C and 15 °C groups. Compared to the 20 °C and 25 °C groups, the activities of the hepatopancreas damage indicators, aspartate aminotransferase, and alanine aminotransferase (ALT) were both increased in the 30 °C group, and the ALT activity was increased in the 10 °C and 15 °C groups. The activity of antioxidant and immune enzymes showed a decreasing trend, while their corresponding gene expression first increased and then decreased as the temperature decreased. In addition, malondialdehyde content was increased in the 30 °C group compared to the 25 °C group. These results indicated that the optimal growth temperature of C. destructor was 20–25 °C. High temperature may induce oxidative stress which in turn damages the hepatopancreas function of crayfish, thereby reducing antioxidant and immune ability. Low temperature may inhibit the development of the hepatopancreas, thereby affecting its function, resulting in decreased immune defenses and ultimately growth inhibition.