title: Feeding on microbiomes: effects of detritivory on the taxonomic and phylogenetic bacterial composition of animal manures.
abstract: Earthworms play a key role in nutrient cycling by interacting with microorganisms thus accelerating organic matter turnover in soil systems. As detritivores, some earthworm types ingest and digest a mixture of dead organic matter and microorganisms, like animal manures (i.e. animal gut microbiomes). Here we described the earthworm cast microbiome and the role ingested bacteria play on its composition. We fed Eisenia andrei with cow, horse and pig manures and determined the taxonomic and phylogenetic composition of the these manures before and after passage through the earthworm gut. Earthworm cast microbiomes showed a smaller diversity than the manure they fed on. Manures strongly differed in their taxonomic and phylogenetic composition, but these differences were markedly reduced once transformed into earthworm cast microbiomes after passage through the earthworm gut. The core earthworm cast microbiome comprised 30 OTUs (2.6% of OTUs from cast samples), of which 10 are possibly native to the earthworm gut. Most of the core cast microbiome OTUs belonged to phyla Actinobacteria and Proteobacteria, as opposed to already described animal core gut microbiomes, which are composed mainly of Firmicutes and Bacteroidetes. Our results suggest that earthworms build up their cast microbiome by selecting from the pool of ingested bacteria.
authors.affiliation: Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Vigo, E-36310. Spain aira@uvigo.es.
authors.forename: Manuel
authors.initials: M
authors.lastname: Aira
authors.affiliation: Brigham Young University, 4102 LSB Provo, UT 84602, USA.
authors.forename: Seth
authors.initials: S
authors.lastname: Bybee
authors.affiliation: CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal Computational Biology Institute, George Washington University, Ashburn, VA 20147, USA Department of Invertebrate Zoology, US National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA.
authors.forename: Marcos
authors.initials: M
authors.lastname: Pérez-Losada
authors.affiliation: Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, Vigo, E-36310. Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Domínguez
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D041963:Bacteroidetes / Q000235:genetics; D044822:Biodiversity; D002417:Cattle; D006736:Horses; D008372:Manure / Q000382:microbiology*; D064307:Microbiota; D009835:Oligochaeta / Q000382:microbiology; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D013552:Swine
chemical_list: D008372:Manure; D012336:RNA, Ribosomal, 16S
keywords: Bar-coded pyrosequencing; Eisenia andrei; bacterial communities; bacterial diversity; core microbiome; earthworm