Crespo‑Piazuelo, DanielLawlor, PeadarRanjitkar, SamirCormican, PaulVillodre, CarmenBouwhuis, Meike A.Marsh, AlanCrispie, FionaRattigan, RuthGardiner, Gillian E.2023-08-022023-08-022011Crespo-Piazuelo, D., Lawlor, P.G., Ranjitkar, S. et al. Intestinal microbiota modulation and improved growth in pigs with post-weaning antibiotic and ZnO supplementation but only subtle microbiota effects with Bacillus altitudinis. Sci Rep 11, 23304 (2021). https://doi.org/10.1038/s41598-021-01826-xhttp://hdl.handle.net/11019/3060peer-reviewedThe objective was to evaluate the efect of dietary Bacillus altitudinis spore supplementation during day (D)0–28 post-weaning (PW) and/or D29–56 PW compared with antibiotic and zinc oxide (AB+ZnO) supplementation on pig growth and gut microbiota. Eighty piglets were selected at weaning and randomly assigned to one of fve dietary treatments: (1) negative control (Con/Con); (2) probiotic spores from D29–56 PW (Con/Pro); (3) probiotic spores from D0–28 PW (Pro/Con); (4) probiotic spores from D0–56 PW (Pro/Pro) and (5) AB+ZnO from D0–28 PW. Overall, compared with the AB+ZnO group, the Pro/Con group had lower body weight, average daily gain and feed intake and the Pro/Pro group tended to have lower daily gain and feed intake. However, none of these parameters difered between any of the probiotic-treated groups and the Con/Con group. Overall, AB+ZnO-supplemented pigs had higher Bacteroidaceae and Prevotellaceae and lower Lactobacillaceae and Spirochaetaceae abundance compared to the Con/Con group, which may help to explain improvements in growth between D15–28 PW. The butyrate-producing genera Agathobacter, Faecalibacterium and Roseburia were more abundant in the Pro/Con group compared with the Con/Con group on D35 PW. Thus, whilst supplementation with B. altitudinis did not enhance pig growth performance, it did have a subtle, albeit potentially benefcial, impact on the intestinal microbiota.enAttribution-NonCommercial-ShareAlike 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-sa/4.0/Animal physiologyAntimicrobialsApplied microbiologyMicrobial ecologyArticlehttps://doi.org/10.1038/s41598-021-01826-x