Non-targeted blood metabolomics of giraffe and white rhinoceros by 1 H nuclear magnetic resonance spectroscopy

Abstract Background Blood metabolomics is used to study internal or external factors that may affect the cellular processes of a cell, tissue or organ. These factors affect species differently. Metabolome differences may differ in some sexes, but it is not a rule. Nutrition and environmental factors affect most species. Objectives Characterize the blood metabolomes of white rhinoceroses and giraffes. Methods Blood was obtained from 45 free-ranging white rhinoceroses and 19 giraffes. The giraffes were from two different sites, and 6 giraffes were sampled in a following year. A ¹H-NMR metabolomics approach was followed, and statistical analysis of the data was done using MetaboAnalyst 6.0. Results A total of 54 metabolites were identified – 52 in the giraffes and 53 in the white rhinoceroses. Glycocholic acid, cholic acid, and N,N-dimethylformamide were absent in the giraffe blood metabolome while glycine was increased. N,N-dimethylglycine was absent in the white rhinoceros blood metabolome. These differences pointed to white rhinoceroses having altered metabolic pathways for one-carbon metabolism and choline catabolism. Metabolomic differences were observed between white rhinoceros sexes, but not in giraffes. Differences between the giraffe blood metabolomes of different years were observed, specifically pathways that are associated with energy production, and were ascribed to environmental factors of drought and high temperature that affected the diet. Conclusions Differences in metabolomes were observed between white rhinoceros sexes, but not in giraffes. The metabolomes between the two species differ.