Evaluation of the metabolomic profile through ¹H-NMR spectroscopy in ewes affected by hyperketonemia

Ketosis is one of the most important health problems in dairy sheep. The aim of this study was to evaluate the metabolic alterations in hyperketonemic ewes. Forty-six adult Sardinian ewes were enrolled between 7 ± 3 days after partum. Blood samples were collected in Venosafe tubes containing clot activator from jugular vein after clinical examination. The β-hydroxybutyrate (BHB) was evaluated on serum and used to divide ewes into two groups: Group H (serum BHB < 0.86 mmol/L) and Group K (serum BHB ≥ 0.86 mmol/L). Animal data and biochemical parameters of groups were examined with one-way ANOVA, whereas the metabolite significant differences were examined by t-test. A robust principal component analysis model and a heatmap were used to highlight possible common trends among metabolites. Over-representation analysis was performed to investigate metabolic pathways potentially altered in connection with the studied BHB alterations. The metabolomic analysis identified 54 metabolites and 14 were significant. These metabolites indicate altered ruminal microbial populations and fermentations; an interruption of the tricarboxylic acid cycle; initial lack of glucogenic substrates; mobilization of body reserves; the potential alteration of electron transport chain; influence on urea synthesis; alteration of nervous system, inflammatory response, and immune cell function.