(P20-001-23) Investigating Seasonal and Yearly Variations in the Intestinal Microbiome of African Elephants

Objectives: Variations in the composition of the bacteria in the intestinal and fecal microbiomes have been observed as a result of diet modifications, such as soluble fiber and macronutrient content. Previously understudied, the goal of our project is to investigate seasonal and annual alterations in the microbiome of captive African savanna elephants, Loxodonta africana.

Methods: With approval from the Maryland Zoo’s IACUC committee, fecal samples from four captive elephants from four seasons for the years 2016-2017 and 2021-2022 were collected, frozen, and are currently being analyzed. Samples were prepped for DNA extraction according to our elephant dung sample preparation protocol. We used liquid nitrogen to solidify the sample enough to subsequently pulverize it. DNA was then extracted using the ZymoBIOMICS DNA Miniprep Kit, and the isolated DNA was quantified. DNA isolated in 2016-2017 was amplified using 16S rRNA primers, tagged with index primers, sequenced on the Illumina MiSeq, and analyzed via Illumina’s Metagenomics App. DNA isolated in 2021-2022 are currently prepared for sequencing, and relative abundance of selected bacterial groups has been determined with qPCR using taxon-specific primers.

Results: Our sequencing data and qPCR analyses suggest that the majority of bacteria detected in all samples belong to the phyla Bacteroidetes (31-42 %) and Firmicutes (22-50 %). Other phyla represented include Proteobacteria (2-4 %), Verrucomicrobia ( < 1 %), and segmented filamentous bacteria ( < 1%). A small seasonal shift in the relative abundance of the major microbial phyla was observed.

Conclusions: Our preliminary analyses suggest that although the zoo diet for the captive elephants only differs slightly among the seasons, small shifts in the relative ratio of bacterial taxa were detectable. Such alterations in the number of bacterial groups observed between seasons or years may be helpful to the curators to explore other ways of augmenting the African elephant’s diet to include those foods that facilitate the growth of beneficial bacterial groups.

Funding Sources: Funding for this project was graciously provided by Jess and Mildred Fischer College of Science and Mathematics at Towson University.