Patterns of Bacterial Community Composition and Diversity Following the Embryonic Development Stages of Macrobrachium rosenbergii

Abstract

During the evolution of aquatic animals, co-evolution between host and microbes has been overlooked. Previous studies have shown that microbes were present in the fertilized egg of fish, but compared with fish, little information is available for crustaceans. High-throughput Illumina Miseq DNA sequencing of the V3-V4 domain of the 16S rRNA gene was used to assess the microbial community composition during different stages of embryonic development in Macrobrachium rosenbergii: fertilized egg stage (OM1), cleavage stage (OM2), blastula stage (OM3), gastrula stage (OM4), egg nauplius stage (OM5), egg metanauplius stage (OM6), protozoea stage (OM7) and zoea stage (OM8). Water samples (WMZ) were also assessed. The results showed that Proteobacteria (82.92%), Bacteroidetes (9.27%), and Actinobacteria (4.49%) were the predominant phylum in the M. rosenbergii embryo. At the genus level, the microbial composition was constantly changing during embryonic development. We concluded that OM3 and OM4 might be the critical stage for transformation of the microbial composition in the M. rosenbergii embryo. The main factor responsible for microbial colonization in the embryo was primarily selective pressure exerted by the shrimp, while the microbial community in the water environment had a lower impact. This study describes bacterial communities in different stages of embryonic development in M. rosenbergii, and the effects of the surrounding environment on microbial colonization. These findings provide valuable information for further studies examining the formation of early intestinal flora in crustaceans.