title: Effects of flavonoids on rumen fermentation activity, methane production, and microbial population.
abstract: This research was carried out to evaluate the effects of flavone, myricetin, naringin, catechin, rutin, quercetin, and kaempferol at the concentration of 4.5% of the substrate (dry matter basis) on the rumen microbial activity in vitro. Mixture of guinea grass and concentrate (60 : 40) was used as the substrate. The results showed that all the flavonoids except naringin and quercetin significantly (P < 0.05) decreased the dry matter degradability. The gas production significantly (P < 0.05) decreased by flavone, myricetin, and kaempferol, whereas naringin, rutin, and quercetin significantly (P < 0.05) increased the gas production. The flavonoids suppressed methane production significantly (P < 0.05). The total VFA concentration significantly (P < 0.05) decreased in the presence of flavone, myricetin, and kaempferol. All flavonoids except naringin and quercetin significantly (P < 0.05) reduced the carboxymethyl cellulase, filter paperase, xylanase, and β -glucosidase activities, purine content, and the efficiency of microbial protein synthesis. Flavone, myricetin, catechin, rutin, and kaempferol significantly (P < 0.05) reduced the population of rumen microbes. Total populations of protozoa and methanogens were significantly (P < 0.05) suppressed by naringin and quercetin. The results of this research demonstrated that naringin and quercetin at the concentration of 4.5% of the substrate (dry matter basis) were potential metabolites to suppress methane production without any negative effects on rumen microbial fermentation.
authors.affiliation: Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia ; Agriculture Biotechnology Research Institute of Iran (ABRII), East and North-East Branch, P.O. Box 91735/844, Mashhad, Iran.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Oskoueian
authors.forename: Norhani
authors.initials: N
authors.lastname: Abdullah
authors.forename: Armin
authors.initials: A
authors.lastname: Oskoueian
mesh_terms: D000821:Animal Feed; D000818:Animals; D002417:Cattle; D002480:Cellulase / Q000378:metabolism; D005285:Fermentation; D005402:Fistula; D005419:Flavonoids / Q000008:administration & dosage*; D008297:Male; D008697:Methane / Q000737:chemistry / Q000378:metabolism*; D012417:Rumen / Q000378:metabolism / Q000382:microbiology*
chemical_list: D005419:Flavonoids; D002480:Cellulase; C019826:carboxymethylcellulase; D008697:Methane