Feed additives may mitigate the risk of virus-contaminated feed
Each operation will need to evaluate cost/benefit to incorporate into their feeding program
By Mark Storlie
Research trials have documented that viruses important to the swine industry can survive in feed ingredients and complete feed for transcontinental (23 days) and transoceanic (30 and 37 days) shipping.
While biosecurity awareness and protocols for animals, people and equipment have increased, feed and feed ingredients may also be routes of virus transmission to be managed.
To evaluate the ability of feed additives to mitigate the risk of virus-contaminated feed, a study evaluated 15 additives across five independent experiments, in facilities that housed 96 pigs per rooms for each treatment.
Each room had separate ventilation systems (air filtered in and out), manure pits, dedicated feed bins and Danish entry system with room-specific coveralls, boots and gloves. Pigs were challenged with equal concentrations of porcine reproductive and respiratory syndrome virus, Senecavirus A and porcine epidemic diarrhea virus.
Table 1 provides a summary of feed additives tested and results observed. Authors reported: “Under the conditions of this study, it appeared that the majority (14 of 15; Vigilex was the exception) of products significantly improved pig health and performance as compared to pigs raised on non-mitigated diets.”
Treatment of contaminated feed with 10 out of 15 products led to no signs of clinical disease and a mortality level of ≤1%. Three products had no clinical signs and had 0 or 1 PCR positive samples out of 30 (1 out of 30 could be false positive) for rectal swabs, and serum and tonsil testing.
Additional studies have evaluated additives specifically for African swine fever virus and foot and mouth virus. For ASFV, formaldehyde and a blend of medium-chain fatty acids were evaluated. Both chemical additives reduced ASFV infectivity in a dose-dependent manner.
This study provides evidence that chemical feed additives may potentially serve as mitigants for reducing the risk of ASFV introduction and transmission through feed.
Commercially available formaldehyde and lactic acid products were tested with FMDV. None of the pigs consuming the formaldehyde treated feed became infected. The lactic acid-based feed additive reduced FMDV infectivity in feed, despite questionable reduction in viral viability in the in vitro study.
A fact sheet from Iowa Pork Industry Center, Feed Additives to Mitigate the Risk of Virus-contaminated Feed, focuses on three research papers that evaluated compounds to mitigate virus-contaminated feed. Mark Storlie, Iowa State University extension swine specialist; Chris Rademacher, Iowa State Extension swine veterinarian, and Scott Dee with Pipestone Research are the authors of the fact sheet.
The experimental design, feed additive or compound evaluated and results for specific viruses are highlighted for each paper.
A specific mode of action is not identified. While some products may mitigate the viral load or/and viability in the feed, other products may support the immune system, gut environment or something yet to be determined to support pig productivity similar to non-challenged pigs.
This is exciting research to identify tools which may help reduce or address specific viruses in swine production. Each operation will need to evaluate the cost/benefit to incorporate these products into their feeding program. A source for product formulations, company contacts and relative pricing is highlighted in the fact sheet to encourage producers to learn more.
We acknowledge claims of efficacy for reduction of viral contamination have not been reviewed or approved by the United States Food and Drug Administration for many of the products described in this article. Therefore, there are no claims directed (whether stated or implied) beyond what is provided on the manufacturer label.
Storlie is an Extension swine specialist in the Department of Agriculture and Natural Resources at Iowa State Univesity.
