Comparative analysis of chicken cecal microbial diversity and taxonomic composition in response to dietary variation using 16S rRNA amplicon sequencing

Background: Antibiotic resistance poses a grave threat to One-Health. By replacing antibiotics with non-antibiotic additives (are alternatives to antibiotics, ATAs) like phytogenic feed additives and organic acids in poultry feed. ATAs are a potential alternative as these decline the proliferation of pathogenic bacteria and strengthen gut function in broiler chickens. In this study, we use 16S rRNA amplicon sequencing of the V3-V4 region to evaluate phytogenic feed additives and organic acids on the cecal microbial diversity of broiler chickens. Methods and results: Two hundred & forty broiler chicks were divided into five treatments comprising: a controlled basal diet (CON), antibiotic group (AB), phytogenic feed additives (PHY), organic acids (ORG), and a combination of PHY + ORG (COM). A distinctive microbial community structure was observed amongst different treatments with increased microbial diversity in AB, ORG, and COM (p < 0.05). The synergistic effects of PHY and ORG increased bacterial population of phyla: Firmicutes, Bacteroides, and Proteobacteria in the cecum. The presence of species, Akkermansia muciniphila (involved in mucin degradation) and Bacillus safensis (a probiotic bacterium) were noticed in COM and PHY, respectively. Clustering analysis revealed a higher relative abundance of similar microbial community composition between AB and ORG groups. Conclusions: Treatments with PHY and ORG modified the relative abundance and presence/absence of specific microbiota in the chicken cecum. Hence, cecal microbiota modulation through diet is a promising strategy to reduce cross-contamination of zoonotic poultry pathogens, led to healthy and economical broiler meat.