Combined effects of <i>Macleaya cordata extract</i> and antimicrobial peptides on reproductive performance and oviduct microbiota in Xuefeng black-bone chickens

The inclusion of Macleaya cordata extract (MCE) and antimicrobial peptides (AMP) in animal feed has been shown to improve performance, potentially providing synergistic benefits when applied in combination. This study aims to investigate the potential synergistic effects of MCE and AMP supplementation on reproductive performance and oviduct microbial composition in Xuefeng black-bone chickens. A total of 900 chickens were randomly assigned to 5 groups with 6 replicates of 30 hens. The group A received a basal diet, while the experimental groups (groups B, C, D, and E) were supplemented with either 500 or 1,000 mg/kg of MCE and 200 or 400 mg/kg of AMP for 66 days. The results demonstrated that (1) Group B exhibited a significant increase in laying rate compared to group A (p < 0.05), along with a significant reduction in feed conversion rate (p < 0.05). Moreover, group E exhibited a significant increase in average daily egg weight (p < 0.05), and all experimental groups showed a significant reduction in abnormal egg rates (p < 0.05). (2) Groups B and C exhibited significantly thicker oviduct epithelium compared to group A (p < 0.05). (3) At the phylum level, all dietary treatment groups showed a higher relative abundance of Firmicutes compared to group A, with the highest levels found in group B (p < 0.05). (4) At the genus level, the relative abundance of Faecalibacterium in groups C and E was significantly higher than in group A (p < 0.05).