Can Feed Additives Reduce Viral Contamination of Feed?

Swine Feed
( National Pork Board and the Pork Checkoff )

They are not alive, but they are not exactly dead, either. They can infect anything. Wherever there is life, you’ll find them. 

There’s no doubt about it, viruses are fascinating. Since the first human virus was discovered in 1901, researchers and scientists in both the human and animal health industries have worked diligently to better understand how they work.

Last year, researchers found that under experimental conditions, the right virus paired with the right feed ingredient could potentially survive a journey across the ocean and enter the U.S. feed supply. 

Researchers believe porcine epidemic diarrhea virus (PEDV) was introduced into the U.S. in 2013 by feed. With fears of African swine fever and other foreign animal diseases on U.S. producers’ minds now, reducing risk is critical.

New research from Dr. Diego Diel of South Dakota State University and Dr. Scott Dee of Pipestone Applied Research and sponsored by the Swine Health Information Center (SHIC) shows that specific feed additives have the potential to reduce viral contamination levels in feed.

“Everyone is focusing on storage time, but mitigation is another area of risk management that we’ve been working on for several years on a small scale,” Dee says. 

The reduction of high-risk pathogens in feed with feed additives could be a way for the industry to protect U.S. herds from PEDV, porcine reproductive and respiratory syndrome (PRRS) and other foreign animal diseases. 

A look at the study
In the SHIC-sponsored study, researchers looked at additives (from the feed industry primarily) that have anti-viral properties. Although these additives aren’t labeled as such, Dee says some of them were thought to have an anti-viral effect and the researchers wanted to take a deeper look into their ability to reduce the viral load in a feed.

A select group of additives showed promising efficacy against high-risk pathogens potentially in feed. Investigators investigated potential mitigation periods prior to embarking to the U.S. or upon arrival at the mill and worked with the American Feed Industry Association to select candidate mitigants.

Based on the outcome of previous feed survival studies, investigators selected highest risk combinations of viruses and ingredients for testing.
Although none of the feed additives tested completely inactivated the pathogens, reductions in viral titers on all pathogens studied were observed with mitigants containing various medium-chain fatty acid blends (such as Captisure from Kemin as well as Kansas State University), organic acid mixtures (such as Activate DA from Novus) or formaldehyde plus propionic acid (SalCURB, Kemin).

Building on possibility
Although these results demonstrate that specific feed additives have the potential to reduce viral contamination levels in feed, investigators suggest further studies are needed to assess mitigator mechanism of action. 

In addition, Dee is researching the efficacy of these mitigants in large groups of pigs following natural feed consumption of contaminated and mitigated feed, in conjunction with viral load and product inclusion rate.

“If we can reduce the viral load, the risk goes down, storage time decreases and chances of infecting pigs with lower doses is much more difficult to do,” Dee says. “Mitigation has a lot of potential – we just have to find the right ones that are safe, don’t harm the nutrient value of the feed ingredient and are cost-effective to apply.”

Chemical mitigation of feed alone may not be able to prevent potential transmission of pathogens through feed, so storage time and importation of feed ingredients from known and trusted sources should be utilized to safeguard the U.S. swine industry from unwanted viruses in other regions of the world.

“If you are looking at ways to reduce challenges to the pig, mitigation is a way to get it done,” Dee says. “We have a few candidates with very good promise.” 

Did You Know? 
Virus comes from the Latin word for “poison” or “slimy liquid,” an apt descriptor for the bug that causes flu and the common cold.

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