Effects of immunomodulatory peptides derived from a soil bacterium on caecal microbiota of broilers challenged with Clostridium perfringens

Abstract

Brevibacillus texasporus peptide (BT peptide) is immunomodulatory in poultry and is proposed as a feed additive substitute for antibiotics. In the present study, we performed 16S rRNA gene sequencing to compare development of the caecal microbial communities in Clostridium perfringens-challenged broilers fed a basal diet only or diets containing the BT peptide (48 ppm) or an antibiotic mixture (20 ppm zinc bacitracin and 40 ppm colistin sulphate). A total of 240 chicks were randomly assigned to these three treatments, each group consisting of 80 birds. Birds were challenged once per day between 4 and 10 d posthatch. A total of 65 caecal samples were collected from 6‒8 randomly selected birds in each treatment group f The composition of microbial communities was clearly distinguishable over time. Treatments with challenge and the antibiotic mixture were associated with increased diversity and with higher relative abundances of Alistipes sp. CHKCI003 and Faecalibacterium and lower abundance of Escherichia coli. At the end of the trial, the caecal microbiota in broilers supplemented with BT peptide were dominated by members of Bacteroidaceae. Predicted function analysis revealed marked enrichment of genes involved in ion-coupled transporters and sugar and biotin metabolism in the BT peptide treatment. The results suggest that BT peptide and commonly-used antibiotics have different influences on modulating the composition of caecal microbiota in broilers.