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.

Increasing carbohydrate availability in the hindgut promotes hypothalamic neurotransmitter synthesis: aromatic amino acids linking the microbiota–brain axis

“…The reaction system and PCR conditions used in the present study were referring to a previous study (Zhang et al . ). The primers sequences are listed in Table .…”

Antibiotics‐induced modulation of large intestinal microbiota altered aromatic amino acid profile and expression of neurotransmitters in the hypothalamus of piglets

“…The reaction system and PCR conditions used in present study were referring to a previous study (Zhang et al . ). The sequences of the PCR primers were listed in Table S2.…”

“…The relative quantifications of gene expressions were analyzed by the cycle threshold (Ct) method described previously (Zhang et al . ).…”

Caecal infusion of the short‐chain fatty acid propionate affects the microbiota and expression of inflammatory cytokines in the colon in a fistula pig model

“…The development of the intestinal mucosa immune system is promoted by the early gut microbial colonization (Maslowski and Mackay, 2011;Hansen et al, 2012). Previous studies have reported that intestinal microbes and microbial metabolites, in particularly short-chain fatty acids (SCFAs), were associated with genes related to inflammation expression of intestinal mucosa (Mu et al, 2016;Zhang et al, 2017).…”