Bacterial Community Dynamics in Kumamoto Oyster Crassostrea sikamea Hatchery During Larval Development

Abstract

Increasing evidence indicates that microbes colonized in early life stages have a long-term effect on animal wellbeing in later life stages. Related research is still limited in aquatic animals, particularly in bivalve mollusks. In this study, we analyzed the dynamics of the bacterial composition of the pelagic larval stages (fertilized egg, trochophore, D-stage, veliger, and pediveliger) and the sessile postlarval stage (spat) of Kumamoto oyster (Crassostrea sikamea) and their relationships with the rearing water bacterioplankton in a hatchery by using Illumina sequencing of bacterial 16S rRNA gene. Both bacterioplankton and larval bacterial communities changed greatly over larval development, and the two communities remarkably differed (r = 0.956, P < 0.001), as highlighted by the differences in the dominant taxa and bacterial diversity. Ecological processes of larval bacterial communities were measured by abundance-unweighted and abundance-weighted standardized effect sizes of the mean nearest taxon distance (ses.MNTD). The unweighted ses.MNTD analysis revealed that the deterministic process constrained the larval bacterial assembly, whereas the weighted ses.MNTD analysis showed that larval bacterial composition was initially governed by stochasticity and then gradually by determinism in the later stages. SourceTracker analysis revealed that the larval bacteria were primarily derived from an internal source, mainly from larvae at the present stage. Additionally, the abundances of larval bacterial-mediated functional pathways that were involved in the amino acid, energy, lipid and carbohydrate metabolisms significantly altered with the larval development. These findings suggest that bacteria assemble into distinct communities in larvae and rearing water in the hatchery system, and the dynamics of bacterial community composition in larvae is likely associated with larval developmental stages.

Prokaryotic and Eukaryotic Microbial Community in Kumamoto Oyster (Crassostrea sikamea) Larvae: Response to Antibiotics in Trace Concentration

“…The decrease in the abundances of these known probiotics may have a negative effect on oyster larval growth. Additionally, we observed that Proteobacteria was the most abundant phylum in Kumamoto oyster larvae, which was consistent with the previous reports on the larval microbiome of Kumamoto oyster and eastern oyster [8,31]. It is well known that most members of Proteobacteria are pathogenic, especially Vibrio species [2].…”

Early Succession of Community Structures and Biotic Interactions of Gut Microbes in Eriocheir sinensis Megalopa after Desalination

“…The results suggest that host development may lead to a more dispersed gut bacterial community. This result was steady with previous research, which reported that development could lead to a more mature and complex host gut microbiota, and the more mature the organism, the greater the differences in individual microbial community structure [54,66,67]. Therefore, we concluded that the host was uncovered to microbial successions during ontogeny.…”

The Probiotic Bacillus hwajinpoensis Colonizes the Digestive System of Crassostrea gigas Larvae and Protects Them from Vibrio alginolyticus Infection

“…Epidemiological investigation of hatchery epidemics indicated that Ostreid herpesvirus 1 (OsHV-1), Vibrio algniolyticus, Vibrio mediterranei, and Pseudoalteromonas spp. were the potential pathogenic microorganisms [6][7][8][9]. The poor facilities to eliminate pathogens from seawater, poor biosecurity concepts during the operation, and management were assumed to be responsible for the insufficiency of disease prevention [6,10].…”