Researchers from the Agricultural Research Service (ARS) in collaboration with a scientist from Farleigh Dickinson University, claim that the hob plant (Humulus lupulus) contains bitters acids which are powerful antimicrobials and can be used to control pathogenic bacteria in the intestines of chickens.
The scientists focused on one compound of the hob plant in particular, lupulone, and assessed its ability to control levels of C. perfringens in chickens.
The ARS group said the study, which was published in the Journal of Antimicrobial Chemotherapy, was triggered by the need to find alternatives to antibiotic use in poultry feed as several types of bacteria are building resistance to antibiotics.
The research will be of interest to meat processors as bacteria such as C. perfringens in the intestines of chickens can cause contamination of meat during processing and can also result in significant production losses by causing disease in the broiler chicken, explained the researchers.
C. perfringens are found in low numbers in many foods, particularly in meat and poultry products. It is also present in soil, the intestines of humans and animals, sewage and animal manures.
Food poisoning linked to the pathogen is the third most commonly reported foodborne illness in the US. Infection with the bacteria normally causes diarrhoea and severe abdominal pain. While it may occasionally cause nausea, it rarely causes vomiting or fever.
Unlike many other types of bacteria that cause food borne disease, C. perfringens are not completely destroyed by ordinary cooking as they have been found to produce heat-resistant spores.
Although the bacteria are killed at cooking temperatures, the heat-resistant spores they produce are able to survive and may actually be stimulated by the heat to germinate.
The research team delivered different concentrations of lupulone via water to chickens inoculated with C. perfringens and they found that after 22 days the pathogen counts were significantly reduced in the lupulone-treated group compared to another group of chickens that did not receive the treatment.
The reductions ranged from 30 to 50 per cent, according to the authors.
The researchers concluded that Lupulone administered through they called for further research into the agent as an antibiotic alternative for intestinal infections.
Source: Journal of Antimicrobial Chemotherapy
Published online ahead of print
Antimicrobial activity of lupulone against Clostridium perfringens in the chicken intestinal tract jejunum and caecum
Authors: G. R. Siragusa, G. J. Haas, P. D. Matthews, R. J. Smith, R. J. Buhr, N. M. Dale and M. G. Wise