Files and links (4)
CC BY V4.0, Open Access
Dissertation
The Microbial Link Between a Ruminant and Its Habitat
Washington State University
Doctor of Philosophy (PhD), Washington State University
07/2025
DOI:
https://doi.org/10.7273/000007553
Abstract
Microbial interactions provide critical functions such as nutrient processing in host-associated environments (e.g., the gastrointestinal (GI) tract). Indeed, the mammalian expansion into herbivory was facilitated by the development of diverse gut microbiotas capable of metabolizing recalcitrant plant complex carbohydrates such as cellulose and lignin together with the evolution of Gl tracts comprising fermentative compartments housing these microbiotas (e.g., cecum, rumen). Along with herbivory came exposure to plant secondary metabolites (PSM) produced by plants to defend against herbivory and protect against environmental stressors. In addition to being toxic, PSMs can limit food digestibility thereby reducing the quality of the diet. In response, mammals produce GI and liver enzymes to degrade these toxins; however, host degradation of PSMs is energetically expensive and may shift nutrient allocation away from growth toward detoxification. Through an interdisciplinary effort including captive animal husbandry, experimental trials, microbial ecology, and pharm-ecology, we found that the microbial communities of three species of deer (Alces alces, Odocoileus hemionus, and O. virginianus) were influenced by nutritional characteristics at different scales. We found that large scale differences in geographic region, thus large-scale dietary selection, significantly influenced the microbial diversity and community composition – more so than the GI organ sampled. At a finer scale we found that natural diets, and the nutritional quality of the natural diets, also influenced microbial communities, but in different ways for mule and white-tailed deer. Finally, at the finest scale, we found that certain purified PSMs influenced not just the microbial community of deer but also impacted their behavior and physiological responses. Host-microbiome interactions influence wildlife populations and communities by directly affecting the survival and reproduction of wild herbivores and indirectly the predators that feed on them. Although the network complexities associated with consumption of PSMs are poorly understood, they likely impact these ecological processes. For example, PSM exposure may compound effects of other environmental stressors such as temperature increases, pathogen exposure, and landscape changes among others. Additionally, physiological stress as evidenced by thermal tolerance, metabolic activity, or behavioral changes may all be linked to this process.
Metrics
5 File views/ downloads
13 Record Views
Details
- Title
- The Microbial Link Between a Ruminant and Its Habitat
- Creators
- Katie Lynn Anderson
- Contributors
- Lisa Shipley (Chair)Charles Robbins (Committee Member)Kristen Johnson (Committee Member)Brandon Briggs (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of the Environment (CAHNRS)
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 156
- Identifiers
- 99901239150701842
- Language
- English
- Resource Type
- Dissertation