PS3-7. On Top Dietary Inclusion of Wheat Middlings Modulates Intestinal Inflammation in Post-weaning Piglets Depending on Body Weight

Abstract Post-weaning diarrhea is a major challenge for piglet welfare and farm productivity. With concerns over antibiotic use, dietary strategies are being explored. Wheat middlings, a high-fiber, low-cost wheat by-product, may support gut health and reduce diarrhea incidence. This study aimed to evaluate the effects of on top wheat middlings supplementation in weanling diets on performance and intestinal health, with particular focus on how these effects vary according to early feed intake and body weight (BW) category. Gut health was assessed using the fecal inflammatory biomarker lipocalin-2 (LCN-2), providing non-invasive and localized information about intestinal inflammation. A total of 720 weaned piglets (21 days old) were distributed into 24 pens, with 30 piglets per pen, balanced according to BW category (Heavy, 6.47 ± 0.02kg; Medium, 5.16 ± 0.06kg; Light, 4.04 ± 0.05kg). During the first 14 days post-weaning the piglets received the same diets with the same specifications (EN = 2,423 kcal/kg, CP = 16.9%, Lys SID = 1.2 g/kg), with half the piglets receiving the diet with 10% on top wheat middlings on top (Group WM; NDF = 39%), half without (Group Control). Piglets were weighed at weaning and on day 11, while feed intake (FI) was recorded on days 4, 8, 11, and 15. Fecal samples were collected from an average-weight piglet per pen (12/treatment). Fecal LCN-2 concentrations were determined using an ELISA assay. Data was analyzed in R, considering dietary treatment and BW category as fixed effects. On day 11, Control piglets tended to weigh 80 g more than WM piglets (P = 0.089). Light piglets in the WM group ate 15 g more feed per day than the heavy ones during the first four days (P = 0.003). In the following periods (days 4–8, 8–11, and 11–15), no effect of wheat middlings’ supplementation was observed; however, both heavy and medium piglets consumed on average 10 to 30 g more than the light ones (P 0.001). Additionally, during days 11–15, WM piglets increased their intake by an additional 20 g (P = 0.007). Regarding LCN-2, by day 8 a tendency towards treatment effect was observed, with WM piglets showing approximately half the LCN-2 concentrations of the Control group (P = 0.099). By day 14, a clear effect of BW category was detected within the WM group, as light piglets showed up to six times higher LCN-2 concentrations compared with their group counterparts. The inclusion of 10% on top wheat middling of the weanling diets exerts a beneficial effect in reducing intestinal inflammation measured on day 8 post-weaning. Nevertheless, six days after, the beneficial effect of wheat middlings on intestinal inflammation seems to be closely associated with feed intake dynamics, particularly in lighter animals.