Investigating the effects of capture and nutritional variance on the metabolism of wild bighorn sheep using quantitative 1 H NMR

Abstract

Rocky Mountain bighorn sheep (Ovis canadensis) are iconic symbols of the American West and have adapted to survive in some of the most rugged and remote landscapes of the region. The nutritional status of these animals is a critical determinant of their survival, reproduction, and population dynamics. Better understanding the impact of these stressors is crucial for effective conservation and management of bighorn sheep populations. Conservation efforts have had limited success, partially due to a lack of knowledge about these animals' metabolic characteristics. This study used proton nuclear magnetic resonance (NMR) metabolomics to investigate metabolic pathways underlying capture techniques and nutritional stress in wild bighorn sheep. Metabolomics provides a snapshot of an organism's metabolic state, identifying physiological markers of stress, nutrition, and health. This research aims to inform conservation practices that promote population resilience. Research on wild bighorn sheep capture focused on understanding the physiological impacts of different animal capture methods. Using NMR-based metabolic profiling, metabolic changes resulting from darting, drop-net, and helicopter captures were compared. Each technique induced distinct metabolic responses, emphasizing the importance of standardized protocols to minimize metabolic stress in wildlife research. The findings highlight the need for careful consideration of capture techniques to ensure animal welfare and obtain reliable physiological data. During winter, when forage is scarce, bighorn sheep rely on body reserves and experience severe nutritional deficits. To study these poorly understood metabolic adaptations, serum samples were collected from free-ranging sheep at different stages of nutritional stress using helicopter capture. Results revealed distinct metabolic profiles associated with early and severe nutritional deficiency, highlighting disruptions in one-carbon, amino acid, and central carbon metabolism pathways. Key metabolites including formate, glucose, and choline showed significant differences between nutritional states, serving as indicators of energy utilization, immune function, and protein catabolism during stress. These findings provide a framework for understanding how capture techniques and nutritional variance impact bighorn sheep metabolism, with direct implications for conservation strategies. These insights will enhance population health monitoring and capture methodologies, supporting the conservation of these emblematic ungulates.