Inhibition of fructan-fermenting equine faecal bacteria and Streptococcus bovis by hops (Humulus lupulus L.) β-acid.
Abstract: The goals of this study were to determine if β-acid from hops (Humulus lupulus L.) could be used to control fructan fermentation by equine hindgut micro-organisms, and to verify the antimicrobial mode of action on Streptococcus bovis, which has been implicated in fructan fermentation, hindgut acidosis and pasture-associated laminitis (PAL) in the horse. Results: Suspensions of uncultivated equine faecal micro-organisms produced fermentation acids when inulin (model fructan) was the substrate, but β-acid (i.e. lupulone) concentrations ≥9 ppm inhibited lactate production and mitigated the decrease in pH. Inulin-fermenting Strep. bovis was isolated from the β-acid-free suspensions after enrichment with inulin. The isolates were sensitive to β-acid, which decreased the viable number of streptococci in faecal suspensions, as well as growth, lactate production and the intracellular potassium of Strep. bovis in pure culture. Conclusions: These results are consistent with the hypothesis that hops β-acid prevented the growth of fructan-fermenting equine faecal bacteria, and that the mechanism of action was dissipation of the intracellular potassium of Strep. bovis. Conclusions: Bacterial hindgut fermentation of grass fructans has been linked to PAL and other metabolic disorders in horses. Hops β-acid is a potential phytochemical intervention to decrease the growth of bacteria responsible for PAL.
© 2014 The Society for Applied Microbiology. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
Publication Date: 2014-05-14 PubMed ID: 24775300DOI: 10.1111/jam.12532Google Scholar: Lookup
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- Journal Article
Summary
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This research aimed to determine if β-acid from hops could control fructan fermentation in horse gut bacteria and explored its action on Streptococcus bovis, a bacteria associated with metabolic disorders in horses. The results showed that β-acid could indeed inhibit lactate production, maintain pH levels, and limit bacterial growth, thereby demonstrating its potential application in mitigating health issues related to fructan fermentation in horses.
Objective and Methodology
- The objective of the study was to investigate if β-acid from hops can control fructan fermentation, a process that has been linked to metabolic disorders in horses, specifically focusing on its action against Streptococcus bovis bacteria.
- The researchers employed suspensions of equine faecal microorganisms and used inulin, a model fructan, as the substrate for bacterial growth.
- The observable factors for experimentation were lactate production, pH decrease, and the effect on the number of viable Streptococcus bovis in the faecal suspensions.
Key Results
- The study found that when the concentration of β-acid was more than or equal to 9ppm, there was inhibition of lactate production and the decrease in pH was mitigated. Lactate production is generally associated with hindgut acidosis in horses, a condition that can lead to metabolic disorders.
- Strep. bovis which are responsible for fructan fermentation were sensitive to β-acid. This indicated that β-acid could effectively control the growth of these bacteria, thereby having the potential to control fructan fermentation.
- The mechanism of action was through the dissipation of intracellular potassium of Strep. bovis. This could potentially interfere with crucial bacterial functions, inhibiting their growth.
Implications and Conclusions
- These findings suggest that hops β-acid could play a critical role in controlling bacterial hindgut fermentation in horses, which is linked to various health issues including pasture-associated laminitis (PAL).
- Hence, β-acid from hops emerges as a potential phytochemical intervention to decrease the growth of such harmful bacteria in horses, improving their metabolic health and reducing the risk of disorders like PAL.
Cite This Article
APA
Harlow BE, Lawrence LM, Kagan IA, Flythe MD.
(2014).
Inhibition of fructan-fermenting equine faecal bacteria and Streptococcus bovis by hops (Humulus lupulus L.) β-acid.
J Appl Microbiol, 117(2), 329-339.
https://doi.org/10.1111/jam.12532 Publication
Researcher Affiliations
- Department of Animal and Food Sciences, University of Kentucky, Lexington, KY, USA.
MeSH Terms
- Animals
- Anti-Bacterial Agents / chemistry
- Anti-Bacterial Agents / pharmacology
- Bacteria / drug effects
- Bacteria / isolation & purification
- Feces / microbiology
- Fermentation / drug effects
- Horses / microbiology
- Humulus / chemistry
- Hydrogen-Ion Concentration
- Inulin / metabolism
- Streptococcus bovis / drug effects
- Streptococcus bovis / metabolism
- Terpenes / chemistry
- Terpenes / pharmacology
Citations
This article has been cited 8 times.- Deng P, Valentino T, Flythe MD, Moseley HNB, Leachman JR, Morris AJ, Hennig B. Untargeted Stable Isotope Probing of the Gut Microbiota Metabolome Using (13)C-Labeled Dietary Fibers. J Proteome Res 2021 May 7;20(5):2904-2913.
- Harlow BE, Flythe MD, Kagan IA, Goodman JP, Klotz JL, Aiken GE. Isoflavone supplementation, via red clover hay, alters the rumen microbial community and promotes weight gain of steers grazing mixed grass pastures. PLoS One 2020;15(3):e0229200.
- Hoffman JB, Flythe MD, Hennig B. Environmental pollutant-mediated disruption of gut microbial metabolism of the prebiotic inulin. Anaerobe 2019 Feb;55:96-102.
- Singh V, Yeoh BS, Chassaing B, Xiao X, Saha P, Aguilera Olvera R, Lapek JD Jr, Zhang L, Wang WB, Hao S, Flythe MD, Gonzalez DJ, Cani PD, Conejo-Garcia JR, Xiong N, Kennett MJ, Joe B, Patterson AD, Gewirtz AT, Vijay-Kumar M. Dysregulated Microbial Fermentation of Soluble Fiber Induces Cholestatic Liver Cancer. Cell 2018 Oct 18;175(3):679-694.e22.
- Hartinger T, Gresner N, Südekum KH. Does intra-ruminal nitrogen recycling waste valuable resources? A review of major players and their manipulation. J Anim Sci Biotechnol 2018;9:33.
- Zou J, Chassaing B, Singh V, Pellizzon M, Ricci M, Fythe MD, Kumar MV, Gewirtz AT. Fiber-Mediated Nourishment of Gut Microbiota Protects against Diet-Induced Obesity by Restoring IL-22-Mediated Colonic Health. Cell Host Microbe 2018 Jan 10;23(1):41-53.e4.
- Harlow BE, Lawrence LM, Harris PA, Aiken GE, Flythe MD. Exogenous lactobacilli mitigate microbial changes associated with grain fermentation (corn, oats, and wheat) by equine fecal microflora ex vivo. PLoS One 2017;12(3):e0174059.
- Harlow BE, Lawrence LM, Hayes SH, Crum A, Flythe MD. Effect of Dietary Starch Source and Concentration on Equine Fecal Microbiota. PLoS One 2016;11(4):e0154037.
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