Key species drive community and functional stability of segment-specific gut microbiomes after the swimming crab...

Molting is a crucial process for crab growth and development. However, the impacts of molting on the structure and function of the gut bacterial community in swimming crab Portunus trituberculatus are poorly understood. Then, dynamic changes in the microbiotas of gut segments (foregut, midgut, and hindgut) after molting were investigated using 16S rRNA gene amplicon and shotgun metagenomic sequencing. We highlight the segment-specific responses in bacterial community compositions, alpha-diversity, and co-occurrence patterns, emphasizing the significant impact of hindgut bacteria on the analysis of the whole gut. The identification of enriched and emerged species and their source, coupled with insights into functional stability and multifunctionality, adds granularity to our understanding of postmolt microbial ecology. We offer potential keys to driving microbial community succession. These findings provide essential insights into the stability and dynamics of gut microbiota, which are crucial for both ecological understanding and sustainable management of crab probiotic regulation.