Submitted to: FEMS Microbiology Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2011
Publication Date: 5/18/2011
Citation: Tillman, G.E., Oakley, B., Haas, G.J., Wise, M.G., Smith, M.A., Siragusa, G.R. 2011. Quantitative Profiling of the Chicken Intestine Microbiome Following Administration of Lupulone, a Plant-Based Antimicrobial.. FEMS Microbiology Ecology. 77(2):395-403. DOI:10.1111/j.1574-6941.2011.01119.x. Interpretive Summary: Antimicrobial resistance is defined as a property of bacteria that confers the capacity to block the inhibitory or killing effects of antibiotics, leading to survival of bacteria despite exposure to antibiotics. The threat of antibiotic resistance has become increasingly of concern in its global dimension and the use of antibiotic growth promoters in poultry has also become an issue. Consequently, it is important to examine other substances as alternatives to antibiotics and determine the effect of these feed additives on the chicken gastrointestinal system. Lupulone, a beta-acid from hops plants, has been considered as a potential feed additive because it can reduce pathogenic bacteria in the gut of chickens when fed to poultry. Lupulone fed to chickens significantly decreased the pathogenic bacterium Clostridium perfringens in the chicken gut. However, bacteria that are considered to have positive effects on growth and health such as the probiotic bacteria Lactobacillus species were not reduced during the feeding of lupulone to chickens. Therefore, lupulone warrants further evaluation as a botanical feed additive to reduce C. perfringens overgrowth during organic or antibiotic-free poultry production.
Technical Abstract: The use of antibiotic growth promoters in poultry rearing is a public health concern due to antibiotic resistance in bacteria and the harboring of resistance genes. Lupulone, a hop beta-acid from Humulus lupulus, has been considered as a potential feed additive. Presently, the effect of lupulone was evaluated for its effect on the microbiome of the chicken intestine. The intestinal microflora of broilers was quantified after addition of lupulone to water and challenge with Clostridium perfringens. Microbial DNA was extracted from the broiler midgut and cecal sections and bacterial groups were quantified using Real-time PCR. The predominant cecal bacterial groups were Clostridium Cluster IV (C. leptum), Clostridium Cluster XIVa and XIVb (C. coccoides) and Bacteroides, whereas Lactobacillus, the Enterobacteriaceae family and Enterococcus dominated the midgut. Lupulone at 125 ppm significantly decreased the Clostridium Cluster I subgroup, which contains C. perfringens, in both the midgut and cecum and Lactobacillus in the midgut. Overall, no significant changes were noted in the microbial profile for the cecum or the midgut. Lupulone warrants further evaluation as a botanical agent to mitigate C. perfringens overgrowth in antibiotic-free reared poultry.