Polyculture Affects the Growth, Antioxidant Status, Nutrient Content, and Flavor of Chinese Mitten Crabs (Eriocheir sinensis) and Largemouth Bass (Micropterus salmoides)

Abstract

Chinese mitten crabs (Eriocheir sinensis) and largemouth bass (Micropterus salmoides) are popular with consumers in China. In recent years, the polyculture of these two species has received more attention, but little is known about how their interactions affect their commercially important traits. In this study, we set up an E. sinensis monoculture group (EM), a M. salmoides monoculture group (MM), and a polyculture group containing both species (EP) and compared the growth parameters, antioxidant statuses, nutritional compositions, and flavor qualities of crabs and fish between the different culture modes. Growth parameters in male crabs and largemouth bass were significantly higher in the EP group than in the EM and MM groups, respectively. Crabs in the EM and EP groups did not differ significantly in malondialdehyde content or glutathione peroxidase activity, regardless of the sampling time, which suggests that crabs in these groups had similar antioxidant and immunity capacities. Compared to the MM group, the activities of superoxide dismutase and catalase of largemouth bass in the EP group were higher, indicating the superior antioxidant capacity of fish in the polyculture mode. Alkaline phosphatase and acid phosphatase activities of both crabs and largemouth bass fluctuated with time in all groups, indicating their important roles in maintaining the health of these cultured species. The amino acid and fatty acid contents of edible tissues were similar between the EM and EP groups and the MM and EP groups, suggesting comparable flavor and quality of edible tissues in crabs and largemouth bass between culture modes. This study provides theoretical support for the polyculture of Chinese mitten crabs and largemouth bass.