Alternative growth promoters alter broiler gut microbiome and enhance body weight gain

Authors: SALAHEEN, SERAJUS - University Of Maryland; KIM, SEON-WOO - US Department Of Agriculture (USDA); Haley, Bradd; Van Kessel, Jo Ann; BISWAS, DEBABRATA - University Of Maryland

Submitted to: American Society for Microbiology Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/19/2017
Publication Date: 5/30/2017
Citation: Salaheen, S., Kim, S., Haley, B.J., Van Kessel, J.S., Biswas, D. 2017. Alternative growth promoters alter broiler gut microbiome and enhance body weight gain. American Society for Microbiology Branch Meeting. May 30, 2017.

Interpretive Summary:

Technical Abstract: Antibiotic growth promoters (AGPs) have commonly been used to enhance growth in poultry production. However, there has been increasing concern over the impact of AGPs use in food production on acquisition of antibiotic resistance in zoonotic bacterial pathogens through inter-bacterial transfer of antibiotic resistance genes (ARGs) in a complex microbial community. In this study, we adopted mass-spectrophtometric, phylogenetic, and metagenomic approaches to evaluate bioactive phenolic extracts (BPE) from blueberry (Vaccinium corymbosum) and blackberry (Rubus fruticosus) pomaces as alternative growth promoters in broilers. We raised 300 Cobb-500 broiler chicks in four groups that were provided water with no supplementation, supplemented with AGP (tylosin, neomycin sulfate, bacitracin, erythromycin, and oxytetracycline), or supplemented with 0.1 or 1.0 g Gallic acid equivalent (GAE)/L of BPE for the six week growth period. When compared with the control group (water only) the chickens that were supplemented with AGP gained 9.5% more body weight and the chickens that were supplemented with 0.1 g GAE/L of BPE gained 5.8% more body weight. The major phenolics that were identified in BPE were apigenin, catechol, chlorogenic acid, coumarin, eugenols, flavan, gallic acid, glucosides, glucuronides, hydroxydaidzein, myricetin, phenols, quercetin, quinones, tannins, triamcinolone, and others. The cecal microbiomes were different among the four groups in respect of bacterial, DNA viral, and archaeal communities. The bacterial community in the BPE-chicken ceca were similar to the microbiome of the AGP-chicken ceca, with higher relative abundance of Firmicutes and lower relative abundance of Bacteroidetes than in the control chicken ceca. AGP supplementation appeared to be associated with phage induction and a more diverse resistome profile in cecal microbiome compared with BPE or control, although both AGP and BPE supplementation resulted in a higher relative abundance of archaea. Functional characterization of cecal microbiomes revealed significant animal to animal variation in the abundance of genes involved in energy and carbohydrate metabolism. Our findings established a baseline upon which mechanisms of plant-based performance enhancers in regulation of animal growth can be investigated. In addition, the data will aid in designing alternate strategies to improve animal growth performance and consequently production.