Metabolomic profiling in umbilical venous plasma reveals effects of dietary rumen‐protected arginine or N‐carbamylglutamate supplementation in nutrient‐restricted Hu sheep during pregnancy

Contents Maternal nutrient restriction during pregnancy is a major problem worldwide for human and animal production. Arginine (Arg) is critical to health, growth and reproduction. N‐carbamylglutamate ( NCG ), a key enzyme in arginine synthesis, is not extensively degraded in rumen. The aim of this study was to investigate ameliorating effects of rumen‐protected arginine ( RP ‐Arg) and NCG supplementation on dietary in undernourished Hu sheep during gestation. From day 35 to 110 of gestation, 32 Hu ewes carrying twin foetuses were randomly divided into four groups: a control ( CG ) group ( n = 8; fed 100% National Research Council ( NRC ) requirements for pregnant sheep), a nutrient‐restricted ( RG ) group ( n = 8; fed 50% NRC requirements, which included 50% mineral–vitamin mixture) and two treatment (Arg and NCG ) groups ( n = 8; fed 50% NRC requirements supplemented with 20 g/day RP ‐Arg or 5 g/day NCG , which included 50% mineral–vitamin mixture). The umbilical venous plasma samples of foetus were tested by 1 H‐nuclear magnetic resonance. Thirty‐two differential metabolites were identified, indicating altered metabolic pathways of amino acid, carbohydrate and energy, lipids and oxidative stress metabolism among the four groups. Our results demonstrate that the beneficial effect of dietary RP ‐Arg and NCG supplementation on mammalian reproduction is associated with complex metabolic networks.