World Aquaculture Society Meetings


Jason Abernathy*, Christos Giatsis and Ken Overturf
Hagerman Fish Culture Experiment Station
3059F National Fish Hatchery Rd
Hagerman, ID 83332

High-throughput sequencing of 16S ribosomal RNA (rRNA) gene amplicons has revealed the diversity of microbial communities (MC) from many different environments and animals. In recent years, much attention has been paid to the intestinal MC and the role they play. The MC in fish intestine is rich and diverse and is thought to serve a crucial role in homeostatic and metabolic processes such as gut functioning and development, immune response and nutrition. Despite significant progress in the discovery of the MC residing in the fish gut, much of the functionality of these communities, fish-microbiota interactions and inter-community interactions remain unclear, as 16S-sequencing does not directly reveal the functional capabilities of the community. Recent studies have indicated, however, that the phylogeny of a community and its functionality are sufficiently linked to allow for a predictive metagenomic approach.

In this study, newly hatched Nile tilapia larvae were reared under two different culture conditions, either a recirculating aquaculture system (RAS) or an active suspension (AS) system. At 42 days post first-feeding, tilapia larvae were randomly collected from RAS and AS replicate tanks and gut samples were processed for high-throughput sequencing of the V1-V2 region of the 16S rRNA gene. Sequencing data was processed using the QIIME software for identification of operational taxonomic units (OTUs). To predict the function of identified bacteria, OTUs were further analyzed using the PICRUSt software. Statistical differences were assessed using the STAMP software. Functional data was mapped to KEGG pathways and orthology.

We identified 44 KEGG ortholog groups with different abundances between aquaculture systems (Figure 1). Further mapping to significant KEGG pathways revealed large differences in abundance of MC contributing to ABC transporters, protein kinases and a host of metabolic processes. Understanding these functional characteristics linked to culture systems may help identify solutions to issues affecting intensive production.

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