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

Research evaluating the possibility of PEDV infection using specialty protein feed ingredients, such as spray-dried plasma of bovine (Pujols and Segales, 2014) and porcine Opriessnig et al., 2014; Foddai et al., 2015; Quist-Rybachuk et al., 2015) origin, has been investigated. Pujols and Segales (2014) found spray-dried bovine plasma when infected with PEDV (2.8 log10 TCID 50 /mL) was not infective in cell culture at 7 d postinoculation when stored at room temperature, and infectivity was lost within 21 d when held at refrigerated temperatures. In the current study, all complete diet and SDPP samples were held at room temperature (approximately 23 °C) following inoculation until addition of PBS at appropriate day of analysis. SDPP not treated with chemical was infective in pig bioassay at 3 d post-laboratory inoculation, whereas infectivity was lost by 21 d indicating infective potential lasted somewhere between 3 and 21 d post-laboratory inoculation in untreated SDPP. Furthermore, SDPP treated with EO and BA was infective at 7 d post-laboratory inoculation, whereas complete swine diet (both untreated and treated with combination of EO and BA) lost infectivity by 1 d post-laboratory inoculation. This direct relationship provides additional evidence that PEDV viability is matrix dependent, and in the current experiment SDPP retained a greater quantity of detectible PEDV genetic material and harbored viable virus for significantly longer than complete swine diet.