Figure 5
The enteroprotective action of in-feed antimicrobials in pigs is associated with increased signaling through intestinal FXR and TGR5. Two independent cohorts of piglets were weaned and fed for 35 days cereal-based diets medicated with combinations of AMA, which were either zinc oxide, amoxicillin, and colistin (ZAC) or zinc oxide, chlortetracycline, and tiamulin (ZCT) at dosing levels routinely used for preventing bacterial enteritis and stimulating pig growth. Control pigs (CON) received no AMA. Gene expression was measured by qRT-PCR in intestinal mucosa samples taken on days 34 and 35. Data from the two experiments were combined in the figure. (A,C) Expression of proinflammatory genes in colon and (B,D) FXR-target genes in ileum of pigs fed CON or medicated (ZAC and ZCT) diets. Data were analyzed with ANOVA. Least squares means ± SEM are plotted, *P < 0.05, **P < 0.01, ***P < 0.001, n = 8–12 per group. (E) Transepithelial electrical resistance (TER) and (F) ion transport (Isc) in the ileal mucosa of pigs fed CON or ZCT. Data were analyzed with ANOVA. Least squares means ± SEM are plotted, *P < 0.05, n = 8. This assay was performed by mounting mucosal segments from the mid-ileum in Ussing chambers from CON and ZCT-treated pigs.
