Gut microbiome architecture of wild greater one-horned rhinoceros: a vulnerable species from Kaziranga National Park, India

Rhinoceros unicornis, also known as the greater one-horned rhinoceros (GoHR), is a vulnerable wildlife species found in the Indian subcontinent with an estimated global population of 3582, of which an estimated 2995 resides in India. The Kaziranga National Park of Assam is the home to ~80.56% of the GoH population in India. Recent advances in genetics and microbial studies underscored the importance of gut microbial symbiosis as a crucial factor for host metabolic health and environmental interaction, particularly for higher mammals. Alteration of the normal microbiome can also be an indicator of chronic disease and infection. Freshly voided dung samples from nine dung heaps of free ranging or wild GoH rhinoceros were collected from Kaziranga National Park for mapping the gut microbial architecture through 16S-metagenomic approach. In our sample, the GoH gut harbours 168.8±12.55 (SE) bacteria-specific OTUs belonging to 21 phyla of which the gram-negative Proteobacteria is the most abundant phyla. Other abundant phylas found in the GoH gut are Firmicutes and Bacteroidetes. Although the GoH rhinoceros gut can utilize fibrous plant by microbial fermentation, the aerobic, nonfermenting Acinetobacter (20.7%), Stenotrophomonas (17.8%) and Brevundimonas (9.1%) constitute about 50% of all identified genus. Functional prediction of the GoH microbiome reveals that >50% of the bacteria present are involved in metabolism followed by cellular processes and information processing. A significant proportion (>1%) are associated with different diseases. In summary, our study characterized bacterial communities of nine wild GoH to identify some unique features and its implication in disease and survival of GoH.