Today I wanted to digest a recent paper published on Transboundary and Emerging Diseases, titled "An evaluation of additives for mitigating the risk of virus‐contaminated feed using an ice‐block challenge model".
Perhaps many in the swine world have already known or heard Dr. Scott Dee talking about this study - this is a collaborated project from Pipestone, Kansas State University, and South Dakota State University and the crew evaluated 15 additives and their effectiveness on mitigating virus-contaminated feed — pretty all the products available out there!
Reducing the risk of viral pathogens is obviously a priority in any swine farms — PRRSV (porcine reproductive and respiratory syndrome), PEDV (porcine epidemic diarrhea virus), and SVA (senecavirus A) are among some of the major concerns.
It was found that these viruses could be transmitted in feed and feed ingredients, and several feed additives are proposed to be able to manage such virus contamination under artificial conditions in small, lab-scale studies.
Therefore, larger scale real-world experiments are needed to increase industry's knowledge in the use of such additives.
Hypothesis: In the presence of virus-contaminated feed, the use of additives would significantly improve pig performance, as compared to pigs on non-mitigated diets.
What was done?
The 15 additives were tested in 5 independent experiment involving 2,880 weaning pigs (5-8 weeks of age). The 5 experiments were conducted at the Pipestone Applied Research facility.
For each experiment, here's what was done:
Note: Feed contamination challenge was done via an ice block model (literally...a 500 ml block of ice — containing equal concentration of PRRSV-174, PEDV and SVA in minimal essential medium — gets dropped in the feed bin on d 0 and d 6 post-challenge).
Products involved in this project:
What was found?
- Did the "ice-block" model work? — Yes. Based on the Positive % in Feed & Oral Fluid data, all 3 viruses consistently entered the rooms via the feed and that viral RNA was subsequently detected in the oral cavities of pigs.
- Growth Performance — Almost all products showed an improvement on ADG and livability compared to Positive Control. Based on a forest plot analysis, on average there was an improvement of 0.18 kg ADG from the use of additives (P < 0.0001).
- Clinical Scores — very clear reduction on the incidence of diarrhoea, lameness, and dyspnoea from majority of the additives.
- Post-mortem diagnostics — Trend pretty much agreed with clinical scores.
Thanks to this extensive work, here is your list of validated products to use for your feed biosecurity program — Majority of these feed additives tested here (14 out of 15) significantly improved the health and performance of pigs exposed to virus-contaminated feeds!
Hoping for a longer list where more products get validated going forward.
(For discussion on the strength & limitations of this project, please do read the full article which has elaborated on each aspect nicely.)
FULL ARTICLE ACCESS👇
Dee, S.A., Niederwerder, M.C., Edler, R., Hanson, D., Singrey, A., Cochrane, R., Spronk, G. and Nelson, E., 2020. An evaluation of additives for mitigating the risk of virus‐contaminated feed using an ice‐block challenge model. Transboundary and Emerging Diseases.
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