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. Newly weaned piglets (n = 216) 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 (d 0 to 9), 2 (d 0 to 16), and 3 (d 16 to 22), respectively. A standard diet was fed during phase 4 (d 22 to 41). On d 5 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 d 5 before challenge (0 d post-inoculation; dpi), d 12 (dpi 7) and d 29 (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 d 0 to 40 average daily gain (ADG) or gain to feed (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 greater ADG from d 0 to 22 compared with pigs fed CTL (P 0.10). Piglets fed CS tended to have heavier d 22 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 less 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 d 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.