Effect of Bacillus subtilis and Oregano Oil on Performance, Gut Microbiome, and Intestinal Morphology in Pullets

This study aimed to examine the effect of probiotics containing Bacillus subtilis and oregano essential oil on growth performance, intestinal morphology, cecal microbial composition in pullets aged 0–18 weeks. A total 324 day-old Hy-Line Brown chicks were randomly assigned three treatment groups, with six replicates per group 18 birds pen. The experimental treatments consisted following: a control receiving basal diet (Con), supplemented 1 g/kg (3 × 108 cfu/kg) (BS), 0.3 (ORO). groups BS ORO demonstrated significantly higher villus height/crypt depth ratios than Con group. Microbial richness was (p = 0.0317) 0.00794) These findings revealed distinct separation between gut communities those ORO, based unweighted weighted UniFrac indices. Therefore, supplementation improved microbiota, suggesting their positive effects health pullets.