PSLBI-20 Dynamic response of piglets fed different sources and levels of fiber during an enterotoxigenic <i>Escherichia coli</i> (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 &amp;gt; 0.10). Overall, pigs fed CS had a greater intake than HFS (P &amp;lt; 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 &amp;lt; 0.10). Piglets fed CS tended to have heavier d 22 BW than CTL (P &amp;lt; 0.10), with HF and HFS intermediate. On dpi 0, butyrate-producing bacteria Lachnospiraceae and Ruminococcaceae were increased in piglets fed a stimbiotic (P &amp;lt; 0.05). On dpi 0 and 7, piglets fed HF had increased abundance of Lachnospiraceae (P &amp;lt; 0.05), whereas no difference was observed on dpi 24 (P &amp;gt; 0.10). Total E. coli did not vary between groups (P &amp;gt; 0.10). On dpi 0, calprotectin concentration was similar between treatments (averaged 25 ng/g feces; P &amp;gt; 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 &amp;lt; 0.05). There was no fiber or fiber × stimbiotic interaction for calprotectin (P &amp;gt; 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.