Intestinal microbiota modulation and improved growth in pigs with post‑weaning antibiotic and ZnO supplementation but only subtle microbiota efects with Bacillus altitudinis

Abstract

The 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.