title: Natural (15)N Abundance in Key Amino Acids from Lamb Muscle: Exploring a New Horizon in Diet Authentication and Assessment of Feed Efficiency in Ruminants.
abstract: Natural (15)N abundance (δ(15)N) varies between individual amino acids (AAs). We hypothesized that δ(15)N of nontransaminating and essential AAs ("source" AAs, such as phenylalanine) present in animal tissues could be used as a marker of dietary origin, whereas δ(15)N of transaminating AAs ("trophic" AAs, such as glutamic acid) could give more detailed insights into animal feed efficiency. Two diets based on dehydrated Lucerne pellets were tested in growing lambs, which promoted different feed efficiencies. No dietary effects were noted on δ(15)N of any AAs analyzed in lamb muscle. In addition, δ(15)N of phenylalanine was unexpectedly similar to that of glutamic acid, suggesting that δ(15)N of AAs is significantly derived from the metabolism of the rumen microbiota and, thus, are not suited for diet authentication in ruminants. In contrast, the δ(15)N of transaminating AAs facilitates an improved prediction of animal feed efficiency compared to the classical isotopic bulk N analysis.
authors.affiliation: UMR 1213 Herbivores, INRA , F-63122 Saint-Genès Champanelle, France.|VetAgro Sup, UMR 1213 Herbivores, Clermont Université , B.P. 10448, F-63000 Clermont-Ferrand, France.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Cantalapiedra-Hijar
authors.affiliation: UMR 1213 Herbivores, INRA , F-63122 Saint-Genès Champanelle, France.|VetAgro Sup, UMR 1213 Herbivores, Clermont Université , B.P. 10448, F-63000 Clermont-Ferrand, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Ortigues-Marty
authors.affiliation: Elucidation of Biosynthesis by Isotopic Spectrometry Group, CEISAM, UMR6230, CNRS-University of Nantes , B.P. 92208, F-44322 Nantes, France.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Schiphorst
authors.affiliation: Elucidation of Biosynthesis by Isotopic Spectrometry Group, CEISAM, UMR6230, CNRS-University of Nantes , B.P. 92208, F-44322 Nantes, France.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Robins
authors.affiliation: Elucidation of Biosynthesis by Isotopic Spectrometry Group, CEISAM, UMR6230, CNRS-University of Nantes , B.P. 92208, F-44322 Nantes, France.
authors.forename: Illa
authors.initials: I
authors.lastname: Tea
authors.affiliation: UMR 1213 Herbivores, INRA , F-63122 Saint-Genès Champanelle, France.|VetAgro Sup, UMR 1213 Herbivores, Clermont Université , B.P. 10448, F-63000 Clermont-Ferrand, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Prache
mesh_terms: D000596:Amino Acids / Q000032:analysis* / Q000378:metabolism; D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D008460:Meat / Q000032:analysis*; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000378:metabolism; D009587:Nitrogen Isotopes / Q000032:analysis* / Q000378:metabolism; D012756:Sheep / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D009587:Nitrogen Isotopes
keywords: 15N; authentication; feed efficiency; irm-GC/MS; ruminants