Establishment of the Bacterial Microbiota in A Lab-Reared Model Teleost Fish, the Medaka Oryzias Latipes

Oryzias latipes is an important model organism for physiology, genetics and developmental studies, and has also emerged a relevant vertebrate model for aquatic ecotoxicology. Knowledge regarding its associ-ated microbiota on the other hand is still scarce and limited to adults, despite the relevance of associated microbiome to hosts biology. This study provides first insights into the establishment of bacterial mi-crobiota during early developmental stages of laboratory-reared medaka using a 16SrRNA sequenc-ing-based approach. Major shifts in community compositions are observed, from a Proteobacte-ria-dominated community in larvae and juveniles to a more phylum diverse community towards adult-hood, with no obvious difference between female and male specimens. Major bacterial taxa found in adults, including genera Cetobacterium and ZOR0006, establish progressively and are rare during early stages. Dominance shifts are comparable to those documented in another major model teleost, the zebrafish. Results from this study provide a basis for future work investigating the influence of meda-ka-associated bacteria during host development.