Dee: Mitigants combined with extended storage time help guard against virus transmission

Feed additives that mitigate viruses, combined with extended storage times, could help protect the US pork industry from African swine fever and other foreign animal diseases, according to Scott Dee, DVM, PhD, director of research, Pipestone Veterinary Services.

Funded by the Swine Health Information Center, Dee’s research compared how 10 different agents used as feed mitigants helped to reduce a quantity of virus in feed ingredients. These include compounds such as organic acids/alkalis, formaldehydes and medium-chain fatty acids.

“We were looking at what we could add to feed that would be safe for consumption but would have a detrimental effect on the virus itself,” Dee explained to Pig Health Today, adding that some of the compounds were already used in feed for other purposes.

Simulated shipment

The American Feed Institute Association canvassed its membership looking for different types of feed mitigants. Ten different products were selected to be tested, Dee reported at the 2018 Leman Swine Conference.

The tests were conducted at South Dakota State University, where the feed infected with the virus and treated with the different mitigants was put through a simulated trans-Pacific shipment. The virus left in the treated feed samples was measured at the end of the 37-day simulation.

“From the 10 we started with, about five have made the cut,” Dee said. These five mitigants, which he described as primarily acids and aldehydes, did significantly reduce the titer in the samples.

“We learned nothing sterilizes the feed,” he continued. “There isn’t one silver bullet you can throw in there and completely negate all virus. We also learned that some of these products already are on the market for other purposes.”

Getting to zero viral load

Since the mitigants do not totally eliminate the virus, Dee believes extended storage time will be needed too. Research has shown that hold times of 78 days after the product’s born-on or packaging date are sufficient for most imported feed ingredients.  A hold time of 286 days is recommended for products containing imported soybean meal.

“We know that, over time, viral load will continue to decay under the concept of half-life,” he said. “That virus will decay and get down to a point where it’s basically zero.

“Mitigation plus storage gives us a two-pronged approach to handle this and, again, take it from a high level down to almost nothing, which is where we want to go.”

North American effort

The use of mitigants and storage to sterilize feed will need to be widely used to be successful. “This has to be an effort at least across the US, across Canada, Mexico,” Dee said. “We’ve got to do this together.

“We’re developing the idea and we want to share it with everybody so they can follow the plan,” he continued. “They can modify it according to their logistics, etc.”

Such a plan for sterilizing feed may also work for US exports. “It could be used to protect our exports, to treat our soy products and ship them out saying not only are we delivering you the best product in the world, it’s also got some protection on it,” Dee added.