Evaluation of a wood-based feed supplement as an alternative to zinc oxide: Effects on growth, antioxidant and inflammatory status, and gut integrity in weaned piglets

From July 2022, the European Union banned therapeutic doses of zinc oxide (ZnO) in animal feed, prompting interest in alternative dietary supplements with antioxidant and anti-inflammatory properties. The study examined the effects of adding a wood-based feed supplement, rich in lignans and phenolic acids, to pre-starter and starter diets on piglet growth performance and intestinal integrity post-weaning. A total of 126 piglets were randomly assigned to three treatments: positive control (PC) and negative control (NC) diets with or without high doses of ZnO in the pre-starter diet (Zn levels exceeding 2500 mg/kg vs. 150 mg/kg), and a diet containing a wood-based supplement (WBS) at a dosage of 1500 mg/kg. Growth parameters were assessed weekly during the post-weaning period. Moreover, blood and fecal samples were collected at 14 days to analyze antioxidant parameters, acute phase proteins, and gene expression related to gut integrity and immune response. No differences in feed conversion ratio were observed among dietary treatments. However, PC and WPS piglets had higher feed intake than those from NC. The growth rate in WPS piglets was intermediate and not different from both control groups. The PC group showed higher relative quantification for IL1β, IFNα, TNFα and occludin than the NC group, whereas piglets fed WBS treatment showed intermediate figures. Overall, the study suggests that dietary inclusion of the wood-based supplement showed promise in promoting increased feed intake and moderate anti-inflammatory activity in weaned piglets, potentially mitigating production losses resulting from the ban on therapeutic levels of ZnO in the early post-weaning period.