Examining the interplay of social status and host gut microbiome composition in male zebrafish (Danio rerio)

Abstract

The gut and the brain, both vastly different in physiologic function, have been linked in a variety of different neurological and behavioral disorders. The bacteria that comprise the gut microbiome communicate with other systems within the body including neurological systems. Specifically, the gut is being associated with the development and onset of many behavioral disorders. Zebrafish (Danio rerio) form social relationships of dominants and subordinates, but the relationship between social status and host gut microbiome is unknown. The purpose of this study was to determine if social status impacts the composition of the host zebrafish by examining how the evolution of social status affects the composition and species diversity of the host gut. After initial isolation, male zebrafish were assigned to one of three experiment groups: paired (n=12), isolate (n=6), or communal (n=6). Over the course of fourteen days, the agonistic interactions of paired zebrafish were observed. To examine fish microbiomes, fecal samples were collected from each fish from each group at four different times: during isolation, on day 0, day 7, and day 14 of pairing. After fecal sample processing and 16S rRNA Illumina sequencing, we found that social status affected host gut microbiome composition. More specifically, bacterial composition differed between fish of different social status and time of experiment. These results are indicative that social status in zebrafish can impact the host gut microbiome with potentially similar effects on other social organisms. This supports the assumptions that social factors may be linked to components of the gut.