PSLBI-20 - Dynamic response of piglets fed different sources and levels of fiber during an enterotoxigenic Escherichia coli (ETEC) challenge in the post-weaning transition

Abstract: Dietary fiber can stimulate the growth of volatile fatty acid-producing bacteria, hence promoting gut health. A stimbiotic can accelerate the settlement of a fiber-fermenting microbiome after weaning. The present study aimed to investigate how different fiber types and a stimbiotic can support microbiome function and resilience of piglets facing an F18 ETEC challenge. A total of 216 newly weaned piglets were blocked by body weight (BW) and randomly assigned to 1 of 4 dietary treatments (n=9), including a corn-soy and wheat middlings control diet (CTL), high fiber diet (HF), CTL plus 0.01% stimbiotic (CS; Signis; AB Vista, UK), and HF plus 0.01% stimbiotic (HFS). The HF diets included sugar beet pulp at 5.0%, 3.8%, 2.5% and soy hulls at 4.0%, 3.0% and 2.0% for phases 1(d0-9), 2(d9-16), and 3(d16-22), respectively. A standard diet was fed during phase 4(d22-41). On d5 post-weaning, all pigs were orally inoculated with 10 ml of F18 ETEC (108 CFU/ml). Twelve piglets were selected from different pens, and a fecal sample was collected on d5 before challenge (0-day post-inoculation; dpi), d12 (dpi 7) and d29 (dpi 24) for analysis of microbial populations by qPCR and fecal calprotectin. Statistical analyses consisted of a multivariate analysis by age, with fiber, stimbiotic, and their interaction as fixed effects. There was no main effect of fiber or stimbiotic on final BW, and d0-40 ADG or G:F (P >0.10). Overall, pigs fed CS had a greater intake than HFS (P< 0.05) with CTL and HF intermediate. Piglets fed CS and HF tended to have higher ADG from d0-22 compared to pigs fed CTL (P< 0.10). Piglets fed CS tended to have heavier d22 BW than CTL (P< 0.10), with HF and HFS intermediate. On dpi 0, butyrate-producing bacteria Lachnospiraceae and Ruminococcaceae were increased in piglets fed a stimbiotic (P< 0.05). On dpi 0 and 7, piglets fed HF had increased abundance of Lachnospiraceae (P< 0.05), whereas no difference was observed on dpi 24 (P >0.10). Total E.coli did not vary between groups (P >0.10). On dpi 0, calprotectin concentration was similar between treatments (averaged 25 ng/g feces; P >0.10) Calprotectin was lower in piglets fed a stimbiotic, at 7 vs 22 ng/g feces on dpi 7, and 8 vs 19 ng/g feces on dpi 24 in the stimbiotic and no stimbiotic group, respectively (P< 0.05). There was no fiber or fiber×stimbiotic interaction for calprotectin (P >0.10). These results demonstrate that feeding high fiber may accelerate the settlement of the piglet microbiome profile as early as 5 days post-weaning. Feeding a stimbiotic may support the resilience of piglets facing an F18 ETEC challenge by promoting the growth of butyrate-producing bacteria, which alleviates the gastrointestinal tract inflammation response and ultimately boost growth performance.