|Buhr, Richard - Jeff|
Submitted to: Antimicrobial Agents and Chemotherapy
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/7/2008
Publication Date: 4/1/2008
Citation: Siragusa, G.R., Haas, G.J., Matthews, P., Smith, R., Buhr, R.J., Macdougald, L., Dale, N. 2008. Humulus lupus Beta-acids Administered Through Water Reduce Clostridium perfringens Challenge Strains in the Chicken Intestinal Tract Midgut and Ceca.. Antimicrobial Agents and Chemotherapy. 61:853-8. Interpretive Summary: Due to concerns over bacterial resistance to human therapeutic antibiotics, researchers are actively seeking alternatives for growth promoting antibiotics fed to livestock and poultry. One candidate alternative might be the antimicrobial compounds found in the plant Humulus lupus, better known as hops. Hops have been part of the beer brewing process for centuries and a portion of these compounds are known to be potent antibacterials. One of these compounds, hop beta-acids, are known to kill the pathogenic bacterium Clostridium perfringens or Cp. Cp is a food borne disease causing bacterium and also causes disease in poultry. In this work we have demonstrated that administering beta acids to poultry by means of the chicken watering system will reduce the levels of Cp in the chicken intestinal tract. This is significant as evidence to further explore beta-acid hop extract as a natural replacement for certain antibiotics currently used to feed livestock.
Technical Abstract: The antimicrobial activity activity of extracts of the hop plant Humulus lupus was studied in chickens fed diets without antibiotic growth promotants. Beta-acid resins of the hop plant were administered by water to 13 day old chickens subsequently challenged per so with necrotic enteritis-associated strains of Clostridium perfringens (Cp) for each of three subsequent days. Culture-based Cp counts of mid-intestinal and cercal contents were compared between chickens administered beta acids at 62.5, 125 and 250 pap in drinking water vs. 0 pap control. No significant differences between control and beta-acid watered groups were observed at day 17 (P>0.05) however, day 22 Cp counts indicated a significant (P<0.05) between reduction in Cp numbers between beta acid treated chickens and control midgut/cecal counts. Within the levels of beta tested no significant (P>0.05) dose response was observed. The potential for beta acids (lupulones) of Humulus lupus as an antibiotic alternative in poultry rearing is considered.