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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #338143

Research Project: Ecology and Molecular Epidemiology of Zoonotic Bacterial Pathogens Asociated with Dairy Farms

Location: Environmental Microbial & Food Safety Laboratory

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

Author
item Salaheen, Serajus - University Of Maryland
item Kim, Seon-woo - US Department Of Agriculture (USDA)
item Haley, Bradd
item Van Kessel, Jo Ann
item Biswas, Debabrata - University Of Maryland

Submitted to: BMC Microbiome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2017
Publication Date: 10/26/2017
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. Front. Microbiol.8:2088. BMC Microbiome. https://doi.org/10.3389/fmicb.2017.02088.
DOI: https://doi.org/10.3389/fmicb.2017.02088

Interpretive Summary: Antimicrobial resistance in human pathogens has become an increasing concern over the last decade. A large percentage of the antibiotics sold in the US is purchased by the animal production industry leading to concerns that the industry is the source of at least some of the bacterial resistance seen in human medicine. Antibiotic growth promoters (AGPs) have commonly been used to enhance growth in broilers and there is pressure on the industry to find alternative products. In this study, we evaluated bioactive phenolic extracts (BPE) from blueberry (Vaccinium corymbosum) and blackberry (Rubus fruticosus) pomaces (berry juice industry byproducts) as alternative growth promoters in broilers. These products have been shown by others to be beneficial in human health. We raised 300 Cobb-500 broiler chicks in four groups that were provided water with no supplementation, supplemented with AGPs (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 positive attributes of the pomace products were attributed to the phenolic compounds found in blueberries and blackberries. The bacterial community (microbiome) present in the lower gastrointestinal tract were different among the four groups. The bacterial community in the BPE-chickens were similar to the microbiome of the AGP-chickens, with higher relative abundance of Firmicutes and lower relative abundance of Bacteroidetes than in the control chickens. AGP supplementation appeared to also be associated with more genes associated with bacterial resistance in the microbiome compared with BPE or control. Functional characterization of 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 future research in designing alternate strategies to improve animal growth performance and consequently production.

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.