Comparative characterization of planktonic and attached bacterial communities in a biofloc-based shrimp (Litopenaeus vannamei) aquaculture system

초록

Microbiota composition of various aquaculture components determines the host’s health and water quality. Despite the growing use of biofloc technology in aquaculture, studies characterizing the microbiota composition of bioflocs and comparing it to microbiota of peripheral rearing water remained rudimentary. To fill this research gap, the present study investigated the biofloc-associated (attached) and rearing water (planktonic) bacterial communities of a commercial shrimp aquaculture system to ascertain how their diversity, community composition, inter-species interactions and functional potential varies. The metataxonomic results, based on high-throughput 16S rRNA gene amplicon sequencing showed that, despite sharing the same niche, the attached community harbors a higher bacterial richness and noticeably different community composition than the planktonic community. Class Alphaproteobacteria (mainly Rhodobacteraceae) preponderated in the attached community, while the planktonic community was dominated by Bacteroidetes (mainly Flavobacteriaceae). By analyzing co-occurrence patterns, we showed a complex ecological network, strong inter-species interactions and diverse keystone taxa in the attached community. Furthermore, members of Halieaceae and Rhodobacteraceae were identified as major keystone taxa in the attached and planktonic communities, respectively, highlighting their vital roles in sustaining the stability of these communities. PICRUSt2-based predictive functional analysis revealed that, in addition to diversity, microbial functional profiles also differed between investigated communities. Overall, we proved that attached and planktonic bacterial communities served as two distinct microbial consortia, each performing different tasks, and hence might play diverse ecological roles in aquaculture systems. Our findings advance scientific understandings of the microbiota variations between planktonic and attached communities in marine environments.