title: Role of Megasphaera elsdenii in the Fermentation of dl-[2-C]lactate in the Rumen of Dairy Cattle.
abstract: Since Megasphaera elsdenii ferments a variable part of dl-lactate to butyrate, measurement of the percentage of dl-lactate fermented to propionate via the acrylate pathway in rumen contents will underestimate the participation of M. elsdenii in the dl-lactate fermentation. The percentage of dl-[2-C]lactate fermented via the acrylate pathway and the percentage of dl-lactate fermented to butyrate can be measured with C-FT (Fourier transform)-nuclear magnetic resonance. On the average, the contribution of M. elsdenii to dl-lactate fermentation in the rumen of dairy cattle was found to be 74% (standard deviation, 13%), but differed with animal or diet. After feeding a cow readily fermentable carbohydrates, the contribution of M. elsdenii to the fermentation of dl-lactate increased as a consequence of catabolite repression in other dl-lactate-fermenting bacteria.
authors.affiliation: Laboratory of Animal Nutrition, Zootechnical Department, State University of Utrecht, Utrecht, The Netherlands.
authors.forename: G H
authors.initials: GH
authors.lastname: Counotte
authors.forename: R A
authors.initials: RA
authors.lastname: Prins
authors.forename: R H
authors.initials: RH
authors.lastname: Janssen
authors.forename: M J
authors.initials: MJ
authors.lastname: Debie