Dissertation
CHARACTERIZING ECTOPARASITE DISEASE PRESSURE AND THE UTILITY OF ANTIBODY MARKERS FOR IMMUNE DEFENSE IN POULTRY
Washington State University
Doctor of Philosophy (PhD), Washington State University
05/2024
DOI:
https://doi.org/10.7273/000006552
Abstract
Open-environment farms are increasingly popular alternatives to conventional caged poultry farms. However, poultry are at an increased risk of exposure to parasites and pathogens in these alternative farming systems, impacting poultry health and leading to economic losses. Two relevant issues are (1) that pressures from ectoparasites are unknown and (2) the immune metrics used to enhance poultry health are unreliable. As a result, the full extent of disease risk on open-environment farms is unclear and the options for managing infectious diseases are limited. The aim of this study was to (1) determine ectoparasite pressures associated with alternative farming systems, (2) critically analyze methods used to measure natural antibodies (NAbs) as immune indices, and (3) to evaluate purported characteristics of NAbs that are considered important to immune defense. Addressing aim 1, I found all surveyed open-environment farms harbored ectoparasites and there was a higher diversity of ectoparasites on open-environment farms compared to conventional systems. These data supported the growing consensus that infectious disease burdens are elevated in open-environment systems. Addressing aim 2, I compared NAb expression among multiple chicken breeds using different assays reported in the literature. These included hemagglutination-hemolysis assays (HA) and enzyme-linked immunosorbent assays (ELISA). I observed that chicken breed affected NAb levels, but breed effects differed among assays. These results illustrated that assay format may bias interpretations of NAbs and obstruct efforts to use NAbs as immune markers. For aim 3, I conducted experiments to test the assumptions that NAbs do not change in response to immune challenge and that they are correlated with expression of adaptive antibodies (AAbs). I evaluated expression of NAbs and AAbs relative to vaccine challenges of multiple chicken breeds and observed that NAbs change in response to vaccination (i.e., immune challenges). In addition, NAbs were not correlated with AAb expression. These results suggest that persistent assumptions about NAb function are unsupported, which is relevant to ongoing efforts to use NAbs in breeding strategies for enhanced immune defense. These data broaden our understanding of disease pressures in poultry farming and identify important knowledge gaps in immunology that are relevant to managing poultry disease.
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Details
- Title
- CHARACTERIZING ECTOPARASITE DISEASE PRESSURE AND THE UTILITY OF ANTIBODY MARKERS FOR IMMUNE DEFENSE IN POULTRY
- Creators
- Kendra N. Weston
- Contributors
- Jeb P Owen (Chair)Allan Felsot (Committee Member)Michael Konkel (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Entomology, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 198
- Identifiers
- 99901121439001842
- Language
- English
- Resource Type
- Dissertation