Evaluating the Efficacy of Commercial Feed Additives As Potential Porcine Epidemic Diarrhea Virus (PEDV) Mitigation Strategies in Complete Feed and Spray-Dried Porcine Plasma As Determined By Polymerase Chain Reaction Analysis and Bioassay

Potential strategies to mitigate the risk of porcine epidemic diarrhea virus (PEDV) transmission in feed and feed ingredients would be valuable for swine producers and feed manufacturers. Research has been conducted assessing potential PEDV mitigation techniques, including the use of medium chain fatty acids, essential oils, organic acids, or formaldehyde, and thermal processing during pelleting of complete diets. Some of these strategies are currently cost prohibitive and not available commercially. A commercial essential oil-based product and a benzoic acid product (CRINA, VevoVitall, respectively; DSM Nutritional Products Inc., Parsippany, NJ) are marketed to improve growth performance. Their chemical composition suggests potential efficacy as a practical, cost effective PEDV mitigation strategy. Therefore, the objective of this study was to determine the impact of VevoVitall (5,000 mg/kg) and/or CRINA (200 mg/kg) as potential chemical mitigation strategies of PEDV in feed and a feed ingredient as determined by qRT-PCR and swine bioassay. Swine gestation diet (FEED) and spray-dried porcine plasma (SDPP) were treated with CRINA and VevoVitall in a 2×2 factorial treatment structure, inoculated with PEDV, stored at room temperature (21ºC), and analyzed on 7 sampling days after inoculation (d 0, 1, 3, 7, 14, 21, 42). On each day of analysis, samples were eluted with PBS and an aliquot submitted for qRT-PCR analysis for PEDV RNA and stored (-80ºC) until determination of infectivity via 10 d old pig bioassay. Data were analyzed using PROC GLIMMIX (SAS Institute, Inc., Cary, NC) to determine main and interactive effects for treatment, feed matrix, and day after inoculation on PEDV Ct values. A marginally significant treatment×feed matrix×day interaction (P=0.082) was observed in which the cycle threshold (Ct) increased over time in FEED when treated with the combination of products (COMBO), whereas there was no increase over time observed in SDPP (d42 Ct=45.0 vs. 29.7, respectively; P<0.001). There was a feed matrix×day interaction (P<0.001) in which the Ct increased over time in FEED, whereas no increase over time was observed in SDPP. Virus shedding was observed in the d 7 post-laboratory inoculation SDPP COMBO treatment, as well as d 0 FEED COMBO treatment. No additional infectivity was observed in FEED (d 1, 3, 7, 14, 21 COMBO treatments). In summary, the combination of CRINA and VevoVitall enhanced degradation of PEDV RNA in FEED, but had no impact on RNA degradation in SDPP. Over time, the infectivity was maintained for a longer duration after inoculation in SDPP than FEED.