Abstract

Macrobrachium rosenbergii , a decapod crustacean belonging to the family Palaemonidae, is one of the most economically valuable freshwater prawn species cultivated worldwide. However, low-temperature has become a major constraint on the sustainable development of its aquaculture. To elucidate the impact of cold stress on M. rosenbergii , this study investigated the effects of 40 days exposure to low temperatures on the growth performance, enzyme activities, gene expression, and muscle nutritional metabolism of M. rosenbergii . The results demonstrated that low temperature reduced the survival rate of M. rosenbergii . Significant decreases in final body weight, final body length, body weight gain rate, and body length gain rate were observed in the 20 and 18 ℃ groups ( P  < 0.05). Low temperature induced elevated activities of antioxidant enzymes (superoxide dismutase (SOD) and total antioxidant capacity(T-AOC)), as well as upregulation of SOD , CAT , HSP70 and HSP90 gene expression. Malondialdehyde (MDA) content in muscle and gill tissues increased significantly in the 20 and 18℃ groups ( P  < 0.05). Furthermore, low temperature altered the nutritional composition of muscle tissue, leading to reductions in ash and crude protein content. Additionally, significant decreases were detected in the contents of delicious amino acids (DAA), essential amino acids (EAA), and key fatty acids such as arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and total n-3 and n-6 polyunsaturated fatty acids ( P  < 0.05). The results indicate that low temperature adversely affects the growth performance and muscle quality of M. rosenbergii .