title: Weaning age influences the severity of gastrointestinal microbiome shifts in dairy calves.
abstract: Ruminants microbial consortium is responsible for ruminal fermentation, a process which converts fibrous feeds unsuitable for human consumption into desirable dairy and meat products, begins to establish soon after birth. However, it undergoes a significant transition when digestion shifts from the lower intestine to ruminal fermentation. We hypothesised that delaying the transition from a high milk diet to an exclusively solid food diet (weaning) would lessen the severity of changes in the gastrointestinal microbiome during this transition. β-diversity of ruminal and faecal microbiota shifted rapidly in early-weaned calves (6 weeks), whereas, a more gradual shift was observed in late-weaned calves (8 weeks) up to weaning. Bacteroidetes and Firmicutes were the most abundant ruminal phyla in pre- and post-weaned calves, respectively. Yet, the relative abundance of these phyla remained stable in faeces (P ≥ 0.391). Inferred gene families assigned to KEGG pathways revealed an increase in ruminal carbohydrate metabolism (P ≤ 0.009) at 9, compared to 5 weeks. Conversely, carbohydrate metabolism in faeces declined (P ≤ 0.002) following a change in weaning status (i.e., the shift from pre- to post-weaning). Our results indicate weaning later facilitates a more gradual shift in microbiota and could potentially explain the negative effects of early-weaning associated with feeding a high-plane of pre-weaning nutrition.
authors.affiliation: UMR Herbivores, INRA, Vetagro Sup, 63122, Saint-Genès-Champanelle, France.
authors.forename: S J
authors.initials: SJ
authors.lastname: Meale
authors.affiliation: Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: S C
authors.initials: SC
authors.lastname: Li
authors.affiliation: Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Azevedo
authors.affiliation: Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: H
authors.identifier: 0000-0001-6079-6563
authors.initials: H
authors.lastname: Derakhshani
authors.affiliation: Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada.
authors.forename: T J
authors.initials: TJ
authors.lastname: DeVries
authors.affiliation: Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: J C
authors.initials: JC
authors.lastname: Plaizier
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada. masteele@ualberta.ca.
authors.forename: M A
authors.initials: MA
authors.lastname: Steele
authors.affiliation: Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada. Ehsan.Khafipour@umanitoba.ca.|Department of Medical Microbiology, University of Manitoba, Winnipeg, MB, Canada. Ehsan.Khafipour@umanitoba.ca.
authors.forename: E
authors.initials: E
authors.lastname: Khafipour
mesh_terms: D000818:Animals; D041963:Bacteroidetes / Q000145:classification / Q000302:isolation & purification*; D050260:Carbohydrate Metabolism; D002417:Cattle; D005243:Feces / Q000382:microbiology*; D000068536:Bacillota / Q000145:classification / Q000302:isolation & purification*; D000069196:Gastrointestinal Microbiome; D010802:Phylogeny; D012417:Rumen / Q000382:microbiology*; D014886:Weaning