Proteome and gut microbiota analysis of Chinese mitten crab (Eriocheir sinensis) in response to Hepatospora eriocheir infection

In recent years, the Chinese mitten crab (Eriocheir sinensis), which is widely farmed in China, has been frequently affected by Hepatospora eriocheir. The gut response of mitten crabs to H. eriocheir infection is not yet known. The aim of this study was to evaluate the effects of H. eriocheir infection on the gut microbiota and proteome of E. sinensis. In this study, E. sinensis was divided into two groups based on whether it was infected with H. eriocheir using PCR and Calcofluor white staining. Calcofluor white staining revealed that H. eriocheir was massively aggregated in the gut. Proteomic results showed that 3959 proteins were identified. Under a 1.2-fold change threshold, 420 differentially expressed proteins (DEPs) were screened, including 292 upregulated DEPs and 128 downregulated DEPs. Differential protein expression related to apoptosis and energy metabolism increased, while protein expression related to immune and inflammatory responses and cell motility decreased. In addition, the microbiota results showed that alpha diversity tended to increase, and beta diversity indicated significant differences in gut microbiota between the two groups. Bacteroidetes, Proteobacteria, and Firmicutes were the dominant phyla in the E. sinensis gut. Compared with the control group, Bacteroidetes were significantly reduced in the infected group, while Firmicutes and Tenericutes were significantly increased. At the genus level, the abundance of Bacteroides, Flavobacterium, Shewanella and Aeromonas decreased significantly, while Candidatus Bacilloplasma, Dysgonomonas, Tyzzerella_3 and Lactovum increased significantly. Microbial function prediction found that most differentially abundant bacteria were related to metabolism. At the same time, correlation analysis between the proteome and gut microbiota found potential roles of differential bacteria and proteins involved in metabolism and immunity. These findings suggest that H. eriocheir infection can alter the gut microbiota composition and proteome of E. sinensis.