title: Diet alters both the structure and taxonomy of the ovine gut microbial ecosystem.
abstract: We surveyed the ruminal metagenomes of 16 sheep under two different diets using Illumina pair-end DNA sequencing of raw microbial DNA extracted from rumen samples. The resulting sequence data were bioinformatically mapped to known prokaryotic 16S rDNA sequences to identify the taxa present in the samples and then analysed for the presence of potentially new taxa. Strikingly, the majority of the microbial individuals found did not map to known taxa from 16S sequence databases. We used a novel statistical modelling approach to compare the taxonomic distributions between animals fed a forage-based diet and those fed concentrated grains. With this model, we found significant differences between the two groups both in the dominant taxa present in the rumen and in the overall shape of the taxa abundance curves. In general, forage-fed animals have a more diverse microbial ecosystem, whereas the concentrate-fed animals have ruminal systems more heavily dominated by a few taxa. As expected, organisms from methanogenic groups are more prevalent in forage-fed animals. Finally, all of these differences appear to be grounded in an underlying common input of new microbial individuals into the rumen environment, with common organisms from one feed group being present in the other, but at much lower abundance.
authors.affiliation: 1Department of Animal Science, University of Wyoming, Laramie, WY, USA.
authors.forename: Melinda J
authors.initials: MJ
authors.lastname: Ellison
authors.forename: Gavin C
authors.initials: GC
authors.lastname: Conant
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Cockrum
authors.forename: Kathy J
authors.initials: KJ
authors.lastname: Austin
authors.forename: Huan
authors.initials: H
authors.lastname: Truong
authors.forename: Michela
authors.initials: M
authors.lastname: Becchi
authors.forename: William R
authors.initials: WR
authors.lastname: Lamberson
authors.forename: Kristi M
authors.initials: KM
authors.lastname: Cammack
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics; D004032:Diet; D017753:Ecosystem; D054892:Metagenome; D012417:Rumen / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D012756:Sheep / Q000382:microbiology*
chemical_list: D004275:DNA, Ribosomal
keywords: 16S subunit; Ovis aries; microbiome