Dietary arginine alleviates the oxidative stress, inflammation and immunosuppression of juvenile Chinese mitten crab Eriocheir sinensis under high pH stress

This study investigates the effect of arginine (Arg) on the growth, antioxidant capacity, inflammation and immunity of juvenile Chinese mitten crab Eriocheir sinensis under high pH stress. Three diets containing 23.7 g/kg (control) 31.4 g/kg and 40.1 g/kg Arg were formulated and fed to crabs (3.37 ± 0.01 g) at high pH (pH = 9.5) for eight weeks. The weight gain and specific growth rate significantly increased in crabs fed the 31.4 g/kg and 40.1 g/kg Arg diets (P < 0.05). Furthermore, Arg improved the antioxidant capacity by increasing the activities of superoxide dismutase, catalase and glutathione production in the hepatopancreas (P < 0.05). In addition, Arg significantly downregulated the inflammatory and apoptotic genes including LPS-induced TNF-α factor, p38 mitogen-activated protein kinase, a disintegrin and metalloprotease 17, Bcl-2-associated X and cysteine-aspartic acid protease 3 (P < 0.05). Arg significantly upregulated the immune genes including crustin, relish and peroxinectin (P < 0.05). The respiratory burst of crabs fed the control diet was significantly lower than those fed the 31.4 g/kg Arg and 40.1 g/kg Arg diets after LPS injection of 0 h, 6 h and 12 h (P < 0.05). This study indicates that dietary Arg can alleviate oxidative stress and inflammation and improve the immunity of juvenile Chinese mitten crab under high pH stress.