Nutrient Deprivation and Wildfire Smoke Inhalation as Environmental Stressors on the Epigenetic Regulation of Liver Biological Age and Blood Proteome of Cattle
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Authors
Fonseca, Mozart Alves
Issue Date
2024
Type
Dissertation
Language
en_US
Keywords
Environmental Stress , Epigenetic clocks , Exposure Science , Proteomics , Wildfire Smoke Inhalation
Alternative Title
Abstract
We investigated the impacts of environmental stressors, specifically nutrient deprivation and wildfire smoke exposure, on the epigenetic aging and proteomic composition of the liver and blood in cattle. Using a controlled stress-induced model, we examined how substantial fluctuations in nutrient intake and exposure to smoke particulate matter affect biological aging markers and resilience in breeding bulls. The study was conducted through a feed restriction phase, followed by compensatory growth, to mimic conditions in extensive production systems. DNA methylation analysis was employed to assess liver epigenetic age, revealing distinct aging patterns across animals. Some bulls exhibited accelerated liver aging during nutrient stress, while others showed signs of epigenetic rejuvenation post-recovery, indicating differential responses to metabolic recovery.We monitored a group of cannulated steers during the 2022 fire season while animals were naturally exposed to wildfire smoke aerosols and performed blood proteomic profiling before, during and post exposure to evaluate immune, inflammatory, and metabolic responses. Proteomics revealed significant changes in protein expression associated with inflammation and immune modulation, highlighting adaptive responses to oxidative stress and airborne particulate matter. These findings provide insights into cattle resilience, emphasizing the importance of understanding epigenetic and proteomic adaptations for animals living under environmental stressors so we can improve animal welfare, health and productive performance in increasingly variable climates. In parallel, to investigate the specific impacts of different types of smoke inhalation, we designed two novel, cost-effective controlled smoke exposure system. The system includes a mask with an adaptable configuration that allows precise regulation of smoke and particulate exposure. Constructed from PVC and 3D-printed components, the mask enables modular attachments, including valves, filters, and mixing chambers for varied particulate and oxidative radical exposure. This system permits controlled, timed smoke exposure intervals, enabling access to physiological and performance effects of smoke inhalation by ruminants in a controlled setting. By providing a platform for studying the health impacts of smoke and particulate matter on livestock, this work contributes to strategic knowledge for producers and policymakers facing seasonal fire risks and air quality reductions, ultimately supporting proactive measures for the development of sustainable ruminant production systems.