Effect of different co-culturing densities of Macrobrachium rosenbergii on the growth performance, nutritional quality, economic benefits and intestinal microbiota of Eriocheir sinensis

This study assessed the effects of different co-culturing densities of giant freshwater prawn ( Macrobrachium rosenbergii ) on water quality, growth performance, nutritional quality, economic benefits and intestinal microbiota of Chinese mitten crab ( Eriocheir sinensis ) ponds. For this purpose, we set three different co-culturing density groups, each with three replicates: 7.5 inds./m 2 (LD), 15 inds./m 2 (MD), 22.5 inds./m 2 (HD). The stocking density of Chinese mitten crab ( Eriocheir sinensis ) was kept consistent in three groups, at 1.50 inds./m 2 . The results showed that there were no adverse effects on the water quality, growth and antioxidant of crabs in three groups. Regardless of sex, the contents of PUFA, C18:2, EPA in the MD group were the highest. The crude fat, crude protein and EAA/TAA ratio of female crabs in the MD group were higher than those of male crabs. This showed that crab in the MD group exhibited superior nutritional value and flavor quality. In terms of economic benefits that year, compared with other co-culturing densities, the crab pond in the MD group could produce higher output value and create additional benefits for farmers. In addition, the crab in the MD group exhibits a relatively higher abundance of Actinobacteria and lower Vibrio . This showed stronger immune regulation ability, which could effectively maintain the homeostasis of intestinal microbial community, so as to reduce the risk of diseases caused by microbial imbalance. This showed that the MD group altered the intestinal microbial community of crab. Considering the water quality, growth, antioxidant capacity, nutritional quality, economic benefits and intestinal microbiota, when the density of M. rosenbergii is 15 inds./m 2 , the nutrition value of crabs is better and it is suitable for crabs to be stocked in the cultivation system.