title: Differential effect of early antibiotic intervention on bacterial fermentation patterns and mucosal gene expression in the colon of pigs under diets with different protein levels.
abstract: The study aimed to evaluate the effects of early antibiotic intervention (EAI) on bacterial fermentation patterns and mucosal immune markers in the colon of pigs with different protein level diets. Eighteen litters of piglets at day (d) 7 were fed creep feed without or with growth promoting antibiotics until d 42. At d 42, pigs within each group were further randomly assigned to a normal- or low-crude protein (CP) diet. At d 77 and d 120, five pigs per group were slaughtered for analyzing colonic bacteria, metabolites, and mucosal gene expressions. Results showed that low-CP diet increased propionate and butyrate concentrations at d 77 but reduced ammonia and phenol concentrations (P < 0.05). EAI increased p-cresol and indole concentrations under normal-CP diet at d 77 (P < 0.05). Low-CP diet significantly affected (P < 0.05) some bacteria groups (Firmicutes, Clostridium cluster IV, Clostridium cluster XIVa, Escherichia coli, and Lactobacillus), but EAI showed limited effects. Low-CP diet down-regulated gene expressions of pro-inflammatory cytokines, toll-like receptor (TLR4), myeloid differentiating factor 88 (MyD88), and nuclear factor-κB p65 (NF-κB p65) (P < 0.05). EAI up-regulated mRNA expressions of interleukin-8 (IL-8) and interferon-γ (IFN-γ) under normal-CP diet at d 77 (P < 0.05). Furthermore, reductions of E. coli and ammonia under low-CP diet were positively correlated with down-regulated gene expressions of pro-inflammatory cytokines, which were positively correlated with the down-regulated TLR4-MyD88-NF-κB signaling pathway. In conclusion, EAI had short-term effects under normal-CP diet with increased aromatic amino acid fermentation and gene expressions of pro-inflammatory cytokines. Low-CP diet markedly reduced protein fermentation, modified microbial communities, and down-regulated gene expressions of pro-inflammatory cytokines possibly via down-regulating TLR4-MyD88-NF-κB signaling pathway.
authors.affiliation: Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China.
authors.forename: Chuanjian
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China.
authors.forename: Miao
authors.initials: M
authors.lastname: Yu
authors.affiliation: Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China.
authors.forename: Chunlong
authors.initials: C
authors.lastname: Mu
authors.affiliation: Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Su
authors.affiliation: Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China. zhuweiyun@njau.edu.en.
authors.forename: Weiyun
authors.initials: W
authors.lastname: Zhu
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D000831:Animals, Newborn; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000254:growth & development; D020148:Butyric Acid / Q000378:metabolism; D003106:Colon / Q000187:drug effects* / Q000378:metabolism / Q000382:microbiology; D004044:Dietary Proteins / Q000008:administration & dosage*; D005285:Fermentation / Q000187:drug effects*; D000069196:Gastrointestinal Microbiome / Q000187:drug effects* / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000382:microbiology; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D010802:Phylogeny; D011422:Propionates / Q000378:metabolism; D015398:Signal Transduction; D013552:Swine; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism; D014886:Weaning
chemical_list: D000900:Anti-Bacterial Agents; D004044:Dietary Proteins; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D010636:Phenols; D011422:Propionates; D051197:Toll-Like Receptor 4; D020148:Butyric Acid; D000641:Ammonia; C029658:propionic acid
keywords: Antibiotic; Gene expression; Low-crude protein diet; Metabolites; Microbiota; Pigs