Abstract

Brevibacillus texasporus peptide (BT peptide) is immunomodulatory in poultry as a feed additive to substitute antibiotics. In the present study we performed 16S rRNA gene sequencing to compare development of the cecal microbial communities in Clostridium Perfringens-challenged broilers fed basal diet only or with either BT peptide (48 ppm) or antibiotics mixture (20 ppm bacitracin zinc and 40 ppm colistin sulfate). 240 chicks were randomly assigned into each treatment and a total of 65 cecal samples were collected at the beginning, during seven challenge days and one week post challenge. The composition of microbial communities was clearly distinguishable over time. Treatments with challenge and the antibiotics mixture were associated with increased diversity and with higher relative abundances of Alistipes sp. CHKCI003 and Faecalibacterium and lower abundance of Escherichia coli (all p<0.05). At the termination of the trial, the cecal microbiota in broilers supplemented with BT peptide was dominated by members of Bacteroidaceae. Predicted function analysis reveals significant enrichment of genes involved in ion-coupled transporters and sugar and biotin metabolism in the BT peptide treatment. Taken together, our results suggest that BT peptide and commonly used antibiotics have different influences on modulating the composition of cecal microbiota in broilers.

Keywords: BT peptide; Antibiotics; Broiler chicken; Bacteria; Clostridium perfringens challenge; Cecal microbiota; 16S rRNA sequencing