Determining the impact of commercial feed additives as potential porcine epidemic diarrhea virus mitigation strategies as determined by polymerase chain reaction analysis and bioassay()

Gebhardt, Jordan T; Woodworth, Jason C; Jones, Cassandra K; Tokach, Mike D; Gauger, Philip C; Main, Rodger G; Zhang, Jianqiang; Chen, Qi; DeRouchey, Joel M; Goodband, Robert D; Stark, Charles R; Bergstrom, Jon R; Bai, Jianfa; Dritz, Steve S

Feed and feed ingredients have been proposed to be contributing factors to the introduction of porcine epidemic diarrhea virus (PEDV) in commercial swine herds (Pasick et al., 2014; Bowman et al., 2015) , and this route of infection has been proven possible in experimental settings (Dee et al., 2014; Pillatzki et al., 2015; Schumacher et al., 2016) . Therefore, potential strategies to mitigate the risk of disease transmission via feed and feed ingredients would be valuable to the swine and feed-manufacturing industries. Research assessing potential mitigation techniques has primarily included two approaches: point-in-time mitigation strategies and mitigation strategies with a prolonged duration of effect. Point-in-time mitigation strategies, such as use of thermal processing or irradiation (Trudeau et al., 2016) , may be efficacious at the time treatment is performed, but the diet remains susceptible to reinoculation posttreatment. Prolonged duration of effect approaches involves the addition of chemical agents to the feed or feed ingredient and remain incorporated through time of consumption such as medium-chain fatty acids (MCFAs), essential oils (EOs), organic acids, or formaldehyde (Dee et al., 2015; Cochrane et al., 2015; Cochrane et al., 2016b; Dee et al., 2016; Trudeau et al., 2016) . With documented evidence of potential for disease transmission via feed or feed ingredients, potential methods to mitigate such risk within a feed-manufacturing facility with a commercially available, safe, and efficacious product that has a prolonged mitigation activity would be valuable. Therefore, the objective of this experiment was to determine the impact of a commercial benzoic acid (BA) product and an EO product as potential chemical mitigation strategies of PEDV in feed and spray-dried porcine plasma (SDPP) as determined by real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and bioassay.