Effect of pre-and probiotics on gut microbiome dynamics in chicken

Abstract

During recent years, the practice of administering antibiotics to animal feed at sub-therapeutic levels has raised concern with consumers because of the apparent increase of antibiotic-resistant bacteria in the human food chain. Researchers have found that probiotics composed of naturally occurring beneficial live microbes such as bacteria (lactobacilli) could be the novel growth promoters. Supplementing poultry diet with probiotics has been found to improve growth performance, feed conversion efficiency, and immune responses, and help in combating enteric pathogens. The aim of this study is to investigate the dynamics of pathogenic bacteria in the gastrointestinal tract of the broiler chickens after adding pre and probiotics to the poultry feed. The experiment consisted of 3 experimental groups reared under the same environmental and lighting regimens; the pre and probiotics group (PB), the antibiotics group (AB), and the control group (C) without any additives. Bacteria were grown on specific agar media and validated via real time PCR. On average, from all the cultured samples, 87.6% were positive for E. coli sp., 27.4% for Shigella sp., 4.4% for Salmonella sp., 53.8% for Campylobacter sp., and 18.1% for Clostridium sp. The specific pathogenic bacteria were evaluated as DNA bands on gel electrophoresis following their amplification by real time PCR. In conclusion, pre and probiotics treatment proved to decrease pathogenic bacteria percentages (except for the Campylobacter sp.) during the late days of the experiment in a similar fashion as antibiotic treatments; suggesting their significant role as an efficient alternative for industrial antibiotics. Lastly, the combination of real time PCR and culture-based methods are both recommended for a better detection of pathogenic bacteria in the broiler gastrointestinal tract.