Changes in the Microbiome and Metabolome in Captive Red Kangaroos (Macropus rufus) Affected by Oral Disease

Red kangaroos (Macropus rufus) are kept in zoos all over the world. Red kangaroos often suffer from oral diseases such as lumpy jaws and have a poor prognosis. Recent studies have shown that oral diseases are caused by a disturbance of oral microbiota. It has also shown that disruption of oral microbiota may affect gut microbiota and be associated with a variety of systemic diseases. However, there have been no reports examining the oral microbiota in red kangaroos, or studies examining how the oral and gut microbiota changes when oral diseases occur. In this study, the microbiome and metabolome of red kangaroos were analyzed using oral swabs, feces and serum to compare the healthy and oral disease groups. Microbiome analysis was performed using 16S rRNA sequencing. Significant changes in both alpha and beta diversity were found in the oral microbiota. In addition to Fusobacterium necrophorum, the most commonly detected species in kangaroos with oral disease, Porphyromonas canoris and Mannhemia granulomatis were characterized in oral disease group. Functional analysis of the oral microbiota showed that pathways related to bacterial infection and the biosynthesis of antibacterial substances were activated in the oral disease group, while the metabolism of many amino acids and fatty acids was inactivated. In fecal microbiota, there were significant changes in beta diversity, with several genera characterized in the oral disease group, but F. necrophorum, P. canoris and M. granulomatis, which were altered in the oral bacteria, were not identified in feces. In this study, each sample was not taken from the same individual and at the same time, so the possibility that individual differences and timing may have influenced the results cannot be ruled out. In addition, the results for oral microbiota and metabolites may vary depending on which part of the oral cavity is used for sampling, and the fecal microbiota may also differ from the microbiota in the intestinal tract.