National Pathogen Collection Center for Aquatic Animals, Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai 201306, China.
Lianyungang Marine and Fisheries Development Promotion Center, Lianyungang Jiangsu 222000, China.
The predatory Bdellovibrio is considered one of the most promising probiotics in aquaculture. Yet the effect of dietary Bdellovibrio probiotics on Chinese mitten crab Eriocheir sinensis has never been evaluated. In the present study, a fifty-day feeding trial was conducted to assess the effects of dietary Bdellovibrio powder at a recommended final dose of 7.5 g kg-1 diets on non-specific immunity, antioxidant ability and disease resistance of E. sinensis. The results indicated that compared with the control, the activities of lysozyme, superoxide dismutase, catalase, acid phosphatase, and alkaline phosphatase were significantly increased in the serum and hepatopancreas of E. sinensis fed with Bdellovibrio powder-supplemented diets (p<0.05). Besides, a significant reduction of malondialdehyde level was also observed in the serum and hepatopancreas of Bdellovibrio powder-fed crabs (p<0.05). In addition, the test crabs fed diets with Bdellovibrio powder for fifty days exhibited significantly (p<0.05) higher protection against aeromonasis, showing a relative percentage survival of 81.25% against Aeromonas veronii challenge for seven days. To conclude, dietary supplementation of Bdellovibrio powder for fifty days can increase immunity, antioxidant capability and resistance of E. sinensis to A. veronii infection.