title: Starter feeding altered ruminal epithelial bacterial communities and some key immune-related genes' expression before weaning in lambs.
abstract: To characterize changes in ruminal epithelial bacterial communities and immune-related gene expression during concentrate starter feeding before weaning in lambs, 6 pairs of 10-d-old Hu lamb twins were selected: 1 kid received milk (M, = 6), and the other received milk plus starter (M+S, = 6). All lambs received hay and water ad libitum and were slaughtered at 56-d-old. Their rumen fluid was collected to determine ruminal pH and VFA levels; rumen epithelia were collected to characterize their bacterial communities using Illumina MiSeq sequencing and to determine mRNA expression of immune-related genes using quantitative real-time PCR (qRT-PCR). Results showed that starter feeding caused a decreased ruminal pH ( = 0.004) and increased concentrations of acetate, propionate, butyrate, and total VFA ( < 0.001). Principal coordinate analysis and analysis of molecular variance revealed that starter feeding affected ruminal epithelial bacterial communities in the lambs ( = 0.001), with higher relative abundance of dominant taxa , unclassified BS11 gut group, , unclassified Synergistaceae, , , , , and ( < 0.05) but lesser relative abundance of , unclassified Bacteroidales, unclassified Candidate, unclassified RF9, and ( < 0.05). Additionally, a phylogenetic investigation of communities by reconstruction of unobserved states analysis indicated that starter feeding markedly increased relative abundance values of dominant ruminal epithelial bacterial-inferred genes related to other ion-coupled transporters, pentose and glucuronate interconversions, glycosyltransferases, other glycan degradation, AA metabolism, sphingolipid metabolism, biotin metabolism, glycosphingolipid biosynthesis-globo series, and lysosome ( < 0.05) but decreased relative abundance values of genes related to carbon fixation pathways in prokaryotes and energy metabolism ( < 0.05) in the lambs. The qRT-PCR results showed that starter feeding decreased the relative mRNA expression of IL-6 ( = 0.003), IL-10 ( = 0.013), and interferon γ ( = 0.003). Collectively, this study showed that starter feeding could alter ruminal epithelial bacterial communities and some key immune-related genes' expression in preweaned lambs. All these responses of ruminal epithelial bacteria and the immune system would be beneficial for starter-fed lambs to be weaned.
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: G
authors.initials: G
authors.lastname: Bian
authors.forename: D
authors.initials: D
authors.lastname: Sun
authors.forename: W
authors.initials: W
authors.lastname: Zhu
authors.forename: S
authors.initials: S
authors.lastname: Mao
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001419:Bacteria / Q000145:classification*; D002087:Butyrates / Q000378:metabolism; D004032:Diet / Q000662:veterinary; D004734:Energy Metabolism / Q000502:physiology; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005786:Gene Expression Regulation / Q000276:immunology*; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D015850:Interleukin-6; D008892:Milk / Q000737:chemistry; D010802:Phylogeny; D011422:Propionates / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012417:Rumen / Q000382:microbiology*; D012756:Sheep / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology*; D014886:Weaning
chemical_list: D002087:Butyrates; D005232:Fatty Acids, Volatile; D007328:Insulin; D015850:Interleukin-6; D011422:Propionates; D016753:Interleukin-10