title: Comparison of milk oligosaccharides between goats with and without the genetic ability to synthesize αs1-casein.
abstract: Milk oligosaccharides (OS)-free complex carbohydrates-confer unique health benefits to the nursing neonate. Though human digestive enzymes cannot degrade these sugars, they provide nourishment to specific commensal microbes and act as decoys to prevent the adhesion of pathogenic micro-organisms to gastrointestinal cells. At present, the limited quantities of human milk oligosaccharides (HMO) impede research on these molecules and their potential applications in functional food formulations. Considerable progress has been made in the study of OS structures; however, the synthetic pathways leading to their synthesis in the mammary gland are poorly understood. Recent studies show that complex OS with fucose andN-acetyl neuraminic acid (key structural elements of HMO bioactivity) exist in goat milk. Polymorphisms in theCSN1S1locus, which is responsible for synthesis of αs1-casein, affect lipid and casein micelle structure in goat milk. The present study sought to determine whetherCSN1S1polymorphisms also influence goat milk oligosaccharide (GMO) production and secretion. The GMO compositions of thirty-two goat milk samples, half of which were from genotype A/A (αs1-casein producers) and half from genotype O/O (αs1-casein non-producers), were determined with nanoflow liquid chromatography high-accuracy mass spectrometry. This study represents the most exhaustive characterization of GMO to date. A systematic and comprehensive GMO library was created, consolidating information available in the literature with the new findings. Nearly 30 GMO, 11 of which were novel, were confirmedviatandem mass spectrometric analyses. Six fucosylated OS were identified; 4 of these matched HMO compositions and three were identified for the first time in goat milk. Importantly, multivariate statistical analysis demonstrated that the OS profiles of the A/A and O/O genotype milks could be discriminated by the fucosylated OS. Quantitative analysis revealed that the goat milk samples contained 1.17 g/L of OS; however, their concentration in milks from A/A and O/O genotypes was not different. This study provides evidence of a genetic influence on specific OS biosynthesis but not total OS production. The presence of fucosylated GMO suggests that goat milk represents a potential source of bioactive milk OS suitable as a functional food ingredient.
authors.affiliation: Department of Food Science & Technology, University of California, Davis 95616, CA, USA ; Foods for Health Institute, University of California, Davis 95616, CA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Meyrand
authors.affiliation: Department of Food Science & Technology, University of California, Davis 95616, CA, USA ; Foods for Health Institute, University of California, Davis 95616, CA, USA.
authors.forename: D C
authors.initials: DC
authors.lastname: Dallas
authors.affiliation: Institut National de la Recherche Agronomique (INRA), UR 631, Station d'Amélioration Génétique des Animaux (SAGA), 31326 Castanet Tolosan, France.
authors.forename: H
authors.initials: H
authors.lastname: Caillat
authors.affiliation: Institut National de la Recherche Agronomique (INRA), UE332 Domaine de Bourges, F-18390 Osmoy, France.
authors.forename: F
authors.initials: F
authors.lastname: Bouvier
authors.affiliation: INRA, UMR1313 - Génétique animale et Biologie intégrative (GABI), Equipe « Lait, Génome & Santé » (LGS), 78350 Jouy-en-Josas, France.
authors.forename: P
authors.initials: P
authors.lastname: Martin
authors.affiliation: Department of Food Science & Technology, University of California, Davis 95616, CA, USA ; Foods for Health Institute, University of California, Davis 95616, CA, USA.
authors.forename: D
authors.initials: D
authors.lastname: Barile
keywords: CSN1S1; Fucose; Genetic polymorphisms; Goat milk; Mass spectrometry; Oligosaccharides