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As new challenging salmonella strains emerge in the poultry industry in Canada, researchers are working with innovative “natural” options to reduce the risk to bird health and food safety.
Dr. Hany Anany has been researching naturally occurring bacterial viruses called bacteriophages, or phages, for more than 15 years for their ability to effectively target salmonella and other troublesome bacteria found throughout poultry production and processing chain. He’s successfully incorporated these beneficial antimicrobials into packaging materials to create anti-salmonella, phage-based bioactive packaging for raw poultry. Now he’s applying that knowledge to use phages to control salmonella in laying hens.
“Phages are highly precise, natural tools that target harmful bacterial like salmonella without impacting beneficial microbes,” says Anany, research scientist with Agriculture and Agri-Food Canada (AAFC) and food safety team lead based at the Guelph Research and Development Centre.
Anany and his team set out to develop and optimize a phage “cocktail” that could effectively control salmonella in laying hens over a wide temperature range. “Using phages to control salmonella in laying hens could help reduce the contamination risk before eggs ever reach the market,” says Anany.
Harnessing viruses for good
Phages are “good” viruses – sometimes called bacteria eaters – that exist throughout the natural world. They are environmentally friendly, very specific to the bacteria they control and able to multiply as needed when faced with high levels of their target bacteria. Phages are found wherever bacteria exist, and those that target salmonella are commonly found where the bacteria circulate in poultry barns.
Anany and his team identified phages that occur naturally in live birds and poultry barns to identify ones that are effective on Salmonella enteritidis, Salmonella Kentucky and other strains having a growing impact on poultry production. They are particularly interested in ensuring the cocktail targets salmonella and doesn’t disrupt the natural gut microflora, which is critical for overall bird health and performance.
“We were able to narrow down a large pool of possible phages to a four-phage cocktail that is highly effective against the salmonella strains we are targeting in laying hens,” says Anany.
“A similar approach could also be translated to broilers and turkey production,” he says. “The key is matching the phage cocktail to the bacterial strains most common in these poultry systems.”
Moving to real-world testing
The phage cocktail has to meet key criteria to successfully move from the lab bench to real-world application. They needed to create an effective process to encapsulate the cocktail to protect and extend its shelf life inside the bird – a dry powder spray that coats the phages before adding to feed.
Working in collaboration with AAFC researcher Dr. Qi Wang, they also needed to show that the mixture would control salmonella inside the bird (41°C) and outside the bird (25°C) in the barn, decrease levels of salmonella in the bird gut and the amount excreted on the eggshell and in litter, be agile against resistant strains, and be easy to administer in feed or water.
“Phages are working well in the lab,” says Anany. “We now want to test whether they can reduce salmonella colonization and shedding in the bird gut, limit contamination of eggs and be applied in the barn environment to further reduce salmonella levels and risk.”
Anany is collaborating with Dr. Nicole Ricker in the Department of Pathology at the Ontario Veterinary College, University of Guelph to feed the phage cocktail to laying hens this fall. After the trials are repeated on layers next year, Anany says they’ll be in a strong position to engage industry partners for scale-up, manufacturing and regulatory planning.
This research is funded by the Canadian Poultry Research Council as part of the Poultry Science Cluster which is supported by Agriculture and Agri-Food Canada as part of the Sustainable Canadian Agricultural Partnership, a federal-provincial-territorial initiative.
