Metatranscriptomic Analysis of the Chicken Gut Resistome Response to In-Feed Antibiotics and Natural Feed Additives

Abstract

The emergence of resistance against common antibiotics in the gut microbiota is a major issue for both human and livestock health. This highlights the need for understanding the impact of such application on the reservoir of antibiotic resistance genes in poultry gut and devising means to circumvent the potential resistome expansion. Phytogenic feed additives (PFAs) are potential natural alternative to antibiotic to improve animal health and performance, supposedly via positively affecting the gut microbial ecosystem, but there is little systematic information available. In this time-course study, we applied a shotgun meta-transcriptomics approach to investigate the impact of a PFA product as well as the commonly used antibiotic, zinc bacitracin either at AGP concentration or therapeutic concentration on the gut microbiome and resistome of broiler chickens raised for 35 days. Over the course of the trial, PFA treatments increased the abundance of Firmicutes such as Lactobacillus and resulted in a lower abundance of Escherichia, while the latter group increased significantly in the feces of chickens that received either AGP or AB doses of bacitracin. Tetracycline resistance and aminoglycoside resistance were the predominant antibiotic resistance gene (ARG) classes found, regardless of the treatment. PFA application resulted in a decrease in abundance of ARGs compared to those in the control group and other antibiotic treatment groups. In summary, the findings from this study demonstrate the potential of phytogenic feed additives could be an alternative to antibiotics in poultry farming, with the added benefit of counteracting antimicrobial resistance development.

Effects of sugarcane extract on growth and diarrhea of growing piglets

“…bation of gut flora homeostasis compared to conventional antibiotic treatments (Hassan et al 2020). SCE belongs to the phenolic PFA group and has a higher antioxidant capacity due to its high phenolic content (Koorakula et al 2022). In this study, the daily feed intake and daily gain of piglets supplemented with SCE did not differ from those of the control group, even though SCE contains more crude protein and fat, which indicated that SCE did not affect the appetite and growth rate of piglets after weaning.…”

Gut Microbiome Studies in Livestock: Achievements, Challenges, and Perspectives

“…Pigs have received special attention in terms of characterization of the gut bacterial resistome, with recent studies demonstrating differential expression in humans, chickens, and specifically pigs [ 158 ]. Yet in chickens, the investigation into the ARGs associated with the gut microbiome has shown that the predominant classes are largely the same as those detected in pigs, including tetracycline, aminoglycoside and macrolide–lincosamide–streptogramin [ 159 ]. Of particular interest and utmost topicality is the risk of the potential transmission of ARGs from poultry meat to humans [ 160 ].…”

Dietary supplementation with probiotics increases growth performance, improves the intestinal mucosal barrier and activates the Wnt/β‐catenin pathway activity in chicks

“…1 However, the increasing spread of marker genes encoding antibiotic resistance and contamination with drug residues are both potential hazards to human health and the environment. 2,3 Antibiotics have been prohibited in the feed of livestock; however, this prohibition resulted in increased disease incidence in intensive poultry production and decreased the efficiency of animal feeding. 4,5 Therefore, there is an urgent need to develop natural substances as antibiotic alternatives.…”

“…For decades, subtherapeutic doses of antibiotic growth promoters have been used to improve the growth rate and feed conversion efficiency of poultry and prevent diseases that occur in intensive farming 1 . However, the increasing spread of marker genes encoding antibiotic resistance and contamination with drug residues are both potential hazards to human health and the environment 2,3 . Antibiotics have been prohibited in the feed of livestock; however, this prohibition resulted in increased disease incidence in intensive poultry production and decreased the efficiency of animal feeding 4,5 .…”