title: Products derived from olive leaves and fruits can alter in vitro ruminal fermentation and methane production.
abstract: BACKGROUND
  The industrial processing of olive generates a high quantity of by-products. The objective of this study was to examine the effects of products derived from olive trees, i.e. leaves, fruits or kernels as a sole substrate (part A), and crude extract from leaves combined with a substrate (part B) on rumen microbial fermentation in an in vitro batch fermentation system. In this study, total gas production, methane production, and concentrations of volatile fatty acids (VFA) and ammonia in ruminal fluid were measured.
  
  
  RESULTS
  In part A, in vitro fermentation of leaves or fruits yielded a gas and total VFA production that were comparable with control substrate, while most of them produced significantly less methane (up to 55.6%) when compared to control substrate. In part B, amongst leaf extracts, only addition of chloroform extract reduced methane production, which was also associated with a decrease (P < 0.01) in gas production. This effect was associated with a significant reduction (P < 0.01) in acetate to propionate ratio and ammonia production, but not in reduction in VFA concentrations.
  
  
  CONCLUSIONS
  Olive leaf and olive leaf chloroform extract reduced ammonia production and increased the molar proportion of propionate in the rumen and can assist in developing novel feed additives for methane mitigation from the rumen. © 2016 Society of Chemical Industry.
authors.affiliation: Animal Sciences Research Section, Kerman Agricultural Research and Education Center, AREEO, Kerman, Iran.
authors.forename: Pirouz
authors.initials: P
authors.lastname: Shakeri
authors.affiliation: School of Animal Biology, The University of Western Australia, M085, 35 Stirling Hwy, Crawley, WA, 6009, Australia.|Future Farm Industries Cooperative Research Centre, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia.
authors.forename: Zoey
authors.initials: Z
authors.lastname: Durmic
authors.affiliation: School of Animal Biology, The University of Western Australia, M085, 35 Stirling Hwy, Crawley, WA, 6009, Australia.|Future Farm Industries Cooperative Research Centre, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia.
authors.forename: Joy
authors.initials: J
authors.lastname: Vadhanabhuti
authors.affiliation: School of Animal Biology, The University of Western Australia, M085, 35 Stirling Hwy, Crawley, WA, 6009, Australia.|Future Farm Industries Cooperative Research Centre, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia.
authors.forename: Philip E
authors.initials: PE
authors.lastname: Vercoe
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000641:Ammonia / Q000378:metabolism; D000818:Animals; D004063:Digestion / Q000187:drug effects; D005285:Fermentation; D019649:Food Industry; D005638:Fruit; D066298:In Vitro Techniques; D008697:Methane / Q000096:biosynthesis*; D031658:Olea; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D011422:Propionates / Q000378:metabolism; D012417:Rumen / Q000187:drug effects* / Q000378:metabolism / Q000382:microbiology
chemical_list: D010936:Plant Extracts; D011422:Propionates; D000641:Ammonia; C029658:propionic acid; D008697:Methane; D019342:Acetic Acid
keywords: VFA; fermentation; in vitro; methane; olive by-products