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

Organic acid feed additives have been long used for control of pathogens, primarily bacteria including Salmonella (Van Immerseel et al., 2006; Carrique-Mas et al., 2007) . Synergistic benefits have been observed at controlling Escherichia coli O157:H7 when combining organic acids with MCFAs (Kim and Rhee, 2013) ; however, limited documentation of co-administration with EOs is available, particularly specific to viral pathogens. Cochrane et al. (2015) used a custom organic acid blend included at 3% including lactic, propionic, formic, and BAs, which resulted in greater loss of PEDV genetic material over time compared to control, with the greatest efficacy observed in spraydried animal plasma compared to other matrices. Trudeau et al. (2016) investigated the use of dietary acidifiers including the commercial products Activate DA (0.4% inclusion; Novus International, St. Charles, MO), KEM-GEST (0.2% inclusion; Kemin Agrifoods, Des Moines, IA), Acid Booster (0.2% inclusion; AgriNutrition, DeForest, WI) and Ultracid P (0.3% inclusion; Nutriaid, Dendermonde, Belgium). Inactivation kinetics were improved with the inclusion of Activate DA, KEM-GEST, and Acid Booster compared to the control samples, indicating that inclusion of dietary acidifiers can increase the rate of inactivation of PEDV when experimentally inoculated in swine feed. In this study, addition of BA alone did not significantly increase PEDV Ct values in FEED nor SDPP. Inclusion rate of the dietary acidifiers evaluated by Trudeau et al. (2016) ranged from 0.2% to 0.4%, whereas inclusion of BA was 0.5% in this study. It is unclear if this difference in inclusion rate or other factors such as specific organic acids used or the specific blend of different organic acids led to the different response than that previously observed by Trudeau et al. (2016) .