Genetically modified tobacco has proven successful in helping reduce potentially fatal post-weaning diarrhea in piglets.
The tobacco contains a protein called FaeG, derived from a bacteria called F4 enterotoxigenic E.coli . This protein prevents pathogenic E. coli, the causal agent of post-weaning diarrhea, from taking hold in piglets’ small intestines.
The genetically modified tobacco is dried and fed in small amounts to the young pigs, as a pharmaceutical feed additive.
In tests at the University of Guelph, graduate student Victoria Seip and Profs. Robert Friendship and Vahab Farzan found that five grams a day of the tobacco, developed by Agriculture and Agri-Food Canada in its London Research and Development Centre, reduced the incidence of diarrhea in three-week-old recently weaned piglets by more than 30 per cent.
Here’s how it works.
Newborn piglets draw immunity from their mothers’ milk against pathogenic E.coli and other bacteria. When the piglets are weaned, they no longer have such protection, and it takes several weeks before they build up their own immunity.
It’s during that time they are most susceptible to the bacteria that cause diarrhea. In about half of the pig population, the cells in their small intestine naturally contain a receptor that allows the bacteria to take hold there and release toxins. Diarrhea develops, and the piglets must be treated with antimicrobials or antibiotics.
“It’s a major concern in the pig industry,” says Seip.
That’s where the protein FaeG comes in. It competes with the pathogenic E.coli for receptor sites. So, with many fewer places to take hold, the E. coli bacteria carry on through the intestines and are eventually excreted.
Previous research conducted by Agriculture and Agri-Food Canada showed that when embedded in dried leaves, the protein did not break down in the digestive tract before having the opportunity to work against the pathogenic E.coli.
Seip says more work must be done before determining whether this treatment is commercially viable, but she’s enthused about results. Seip believes this plant-based product might be an alternative to antibiotics and antimicrobials that are currently added to some starter feeds for piglets, to help them stave off disease
The challenge is to find a way to incorporate the protein into such starter feeds. In the Guelph trials, Seip and research technicians mixed the dried leaf powder with chocolate milk and bottle fed it to the 24 piglets in the study five times before they were introduced to the bacteria, to ensure the animals consistently received the proper dose.
“That wouldn’t be practical in a commercial herd where most producers wean at least 150 pigs per week,” she says. “If the approach is to be offered widely, it will need to be part of feed.”.
Others involved in this study, conducted at Agriculture and Agri-Food Canada, the Arkell Research Station and the Ontario Veterinary College Isolation unit, and the Animal Health Laboratory were Drs. Rima Menassa and Josepha Delay.
This research was sponsored by the University of Guelph-Ontario Ministry of Agriculture, Food and Rural Affairs’ agreement and Swine Innovation Porc.