Hepatic metabolomic investigation of the North American black bear (Ursus americanus) using 1H-NMR spectroscopy

The growing field of metabolomics examines the end products of metabolism, metabolites, to determine physiological processes at a cellular level. Nuclear magnetic resonance (NMR) spectroscopy affords advantages such as noninvasive sample collection, minimal or no sample preparation, and conservation of samples. The objectives of this study were to determine the feasibility of NMR-based metabolomics as a screening tool for evaluating changes in North American black bear (Ursus americanus) metabolism, establish a baseline metabolic profile for the black bear, and determine if there was any significant variation between individual metabolic profiles of hunter-killed bears. Hepatic samples were collected from 14 legally, hunter-killed black bears. The samples were frozen, homogenized, and extracted. 1H NMR spectra were collected and analyzed. Over 30 metabolites were identified, including those involved with protein, lipid, and carbohydrate metabolism. Principal components analysis demonstrated a separation among the bears by general age groups, based on differences in several energy and amino acid biomarkers, as well as lactate. This difference may be due to variation in growth and body composition with age. NMR-based metabolomics proved to be a practical technique for identifying components of black bear metabolism.