Thursday, August 15, 2019: 2:30 PM
L007/008, Kentucky International Convention Center
Keylie M. Gibson1, Bryan N. Nguyen2, Laura M. Neumann3, Michele Miller4,5, Peter Buss6, Savel Daniels7, Michele Ahn1, Keith A. Crandall1 and Budhan S. Pukazhenthi8, (1)Computational Biology Institute, George Washington University, Washington, DC, (2)Department of Biological Sciences, George Washington University, Washington, DC, (3)Department of Environmental and Occupational Health, George Washington University, Washington, DC, (4)South African Medical Research Council Centre for Tuberculosis Research, DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, Cape Town, South Africa, (5)Division of Molecular Biology and Human Genetics, Stellenbosch University, Cape Town, South Africa, (6)South Africa National Parks, Skukuza, South Africa, (7)Department of Botany and Zoology, University of Stellenbosch, Matieland, South Africa, (8)8Smithsonian’s National Zoo and Conservation Biology Institute, Front Royal, VA
Background/Question/Methods: The African black rhinoceros (
Diceros bicornis) had their population decimated by poaching, reducing the population size from 70,000 individuals in 1970 to a low of 2,410 in 1995. Targeted conservation efforts have brought this species back from the brink of extinction to an approximately 5,000 animals today. Part of this rebound is due to the roughly 200 black rhinos (southern and eastern sub-species combined) that reside in zoological institutions world-wide as a reservoir against potential extinction. However, the
ex situpopulation experiences its own threats to survival. The difficulty of providing black rhinos natural diet (in diversity and quantity of browse) is a major challenge to managing black rhinos in captivity. Rhinos maintained in captivity are affected by chronic health issues, but underlying cause(s) remain unknown. To understand the implications of diet (and gut microbiome) on their health, we compared gut microbiomes of wild and captive black rhinos. If differences in microbiome diversity exist between wild and captive rhinos, then the microbiome can be exploited to improve overall health of captive rhinos. Therefore, to characterize, compare, and understand the microbial taxonomic and functional diversity, fecal samples and health information were collected from wild and captive black rhinos. Metagenomic sequencing was performed on these fecal samples to quantify the microbiome diversity and test for differences between the captive and wild rhino gut microbiomes.
Results/Conclusions: Bacterial taxa traditionally associated with ruminant guts of domesticated animals had higher relative abundances in captive rhinos. Our metagenomic sequencing results suggest that unknown gut microbes of wild rhinos are being replaced by those found in conventional human-domesticated livestock. Wild and captive rhinos have functionally distinct bacterial communities (p < 0.001). Functional profiling results showed greater abundance of glycolysis and amino acid synthesis pathways in captive rhino microbiomes, representing an animal receiving sub-optimal nutrition with a readily available source of glucose but possibly an imbalance of necessary macro and micronutrients. Based on our understanding of the impact of the black rhino gut microbiome, we recommend greater attention to nutritional management to enhance overall health for this critically endangered species. Furthermore, sequencing allows for a new minimally invasive technique for evaluating nutrition of captive raised animals and the potential for identifying new microbial species in understudied wild animals.
