In animals, growth and development are strongly correlated with the gut microbiota and metabolic profiles. In this study, gut microbiome communities, metabolic profiles, and growth performance of Eriocheir sinensis under three dietary feed types based on waterweed plants only, freshwater snails only, and waterweed plants combined with freshwater snails were studied by using 16S rRNA gene sequencing and liquid chromatography-mass spectrometry. Results indicated that different feed types dramatically affected the growth performances of E. sinensis by altering the gut microbiota and metabolic profiles. Aquatic plants, such as waterweeds, played essential roles in shaping gut microbiome communities, and the optimal Bacteroides-to-Firmicutes ratio might strongly promote growth performance. Waterweed plants also helped decrease maleficent Proteobacteria caused by excess animal-type feedstuff, such as freshwater snails, and might have positive roles in antibacterial functions in gut. A diet based on waterweeds only resulted in lipid metabolism disorders, which significantly retarded the growth of E. sinensis. In summary, E. sinensis cultured with a diet of waterweeds and freshwater snails showed superior growth performance due to their healthy gut microbiota and metabolic homeostasis. Our findings unveiled the roles of aquatic plants and animal-type food such as freshwater snail in shaping the gut microbiota and metabolic processes and provided guidance for the aquaculture of E. sinensis in future.

Background: Aquatic plants and freshwater snails are important natural food sources of Eriocheir sinensis, which play important roles in the growth and development of E. sinensis. However, research on how aquatic plants and freshwater snails affect the growth and development of E. sinensis remains scant.Methods: The effects of the two kinds of natural food sources on the growth and development of E. sinensis were studied by determining the hepatopancreatic proteomes of three groups, namely, E. sinensis fed with aquatic plants combined with freshwater snails (group A), E. sinensis fed with aquatic plants only (group B), and E. sinensis fed with freshwater snails only (group C), using tandem mass tag technology.Results: A total of 110 differentially expressed proteins between groups A and B were identified, among which 78 were up-regulated and 32 were down-regulated in group A. Meanwhile, nine proteins were up-regulated, and 14 proteins were down-regulated in group A relative to those in group C. The proteins related to molting and growth such as cryptocyanin and cuticle protein CBM were up-regulated in group A compared with group B. The immunity-related proteins, such as mannosyl-oligosaccharide glucosidase and glutathione peroxidase, that were differentially expressed between groups A and C, were up-regulated in group A.Conclusion: The results indicated that freshwater snails might promote the growth and development of E. sinensis to a certain extent, and aquatic plants might play an important role in the immunity of E. sinensis. Our study provides a theoretical basis for the practice of “providing aquatic plants and freshwater snails” in the ecological culture of E. sinensis.

Aquatic plants and freshwater snails are important natural food sources of Eriocheir sinensis. The effects of these two kinds of natural food sources on the growth and development of Eriocheir sinensis were studied by determining the hepatopancreatic proteomes of three crab groups, namely, crabs fed with aquatic plants combined with freshwater snails (group A), crabs fed with aquatic plants only (group B), and crabs fed with freshwater snails only (group C), with tandem mass tag technology. Results showed 110 differentially expressed proteins between groups A and B, among which 78 were up-regulated and 32 were down-regulated in group A. Meanwhile, 9 proteins were up-regulated and 14 proteins were down-regulated in group A relative to those in group C. The proteins related to molting and growth that were differentially expressed between groups A and B were up-regulated in group A. These proteins included cryptocyanin and cuticle protein CBM. The immunity-related proteins, such as mannosyl-oligosaccharide glucosidase and glutathione peroxidase, that were differentially expressed between groups A and C and were up-regulated in group A. These results indicated that freshwater snails might promote the growth and development of E. sinensis to a certain extent, and aquatic plants might play an important role in the immunity of E. sinensis. Our study provides a theoretical basis for the practice of “planting grass and throwing snails” in the green ecological culture of E. sinensis.