title: Effect of the microbial feed additive Saccharomyces cerevisiae CNCM I-1077 on protein and peptide degrading activities of rumen bacteria grown in vitro.
abstract: We investigated the potential of the ruminant feed additive Saccharomyces cerevisiae CNCM I-1077 on protein and peptide degrading activities of the rumen bacterial species Prevotella albensis M384, Streptococcus bovis 20480, and Butyrivibrio fibrisolvens 3071 grown in vitro. Alive or heat-killed yeast cells were added to bacterial cultures in a complex casein-glucose medium. After incubation of the cultures at 39 degrees C under O(2)-free CO(2), peptidase activities were determined in the absence or in the presence of yeasts. Protease activities were detected after PAGE in gelatin-copolymerized gels. In co-incubations of bacteria and live S. cerevisiae I-1077, proteinase activities were reduced compared to the activities in the bacterial monocultures. Measurement of peptidase activities and microbial enumerations in the co-incubations suggested that live yeasts and bacteria interacted in a competitive way, leading to a decrease in peptidase activities. The mechanism responsible for such an effect could be mainly a competition for substrate utilization, but the release of small competitive peptides by the yeast cells is also likely to be implicated.
authors.affiliation: Lallemand Animal Nutrition, Sébastien Masséglia, 19 rue des Briquetiers, BP59, 31702 Blagnac cedex, France. fchauc@clermont.inra.fr
authors.forename: Frédérique
authors.initials: F
authors.lastname: Chaucheyras-Durand
authors.forename: Sébastien
authors.initials: S
authors.lastname: Masséglia
authors.forename: Gérard
authors.initials: G
authors.lastname: Fonty
mesh_terms: D000821:Animal Feed / Q000382:microbiology*; D000818:Animals; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism*; D005503:Food Additives; D005516:Food Microbiology; D066298:In Vitro Techniques; D010447:Peptide Hydrolases / Q000378:metabolism; D012417:Rumen / Q000382:microbiology*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D004044:Dietary Proteins; D005503:Food Additives; D010447:Peptide Hydrolases