Date Full Report Received

12/31/2014

Date Abstract Report Received

12/31/2014

Investigation

Institution:
Primary Investigator:

We studied the effect of low heat (600C, 700C, 800C, and 900C); high heat (1200C, 1300C, 1400C, and 1450C); irradiation; and the addition of drying agents/acidifiers on the killing of PEDV in swine feed. At low heat, we found that PEDV survival depended not only on temperature and relative humidity (RH) but also on the type of feed ingredient used. Heating feed to 600C at any of the 3 RH levels (30%, 50%, and 70%) was not sufficient to inactivate 99.99% of PEDV. However, a combination of 900C and 70% RH killed 99.99% PEDV within 10 to 30 minutes. At high heat, increasing amounts of virus were inactivated with increased temperature; 99.99% virus was inactivated within 10 minutes at 1450C. Virus inactivation by irradiation was dose-dependent; greater than 99.97% virus was inactivated at 50 kGy while only 90% was killed at 10 kGy. We evaluated six different additives on the inactivation of PEDV in feed and found that the addition of sugar and salt was as good in killing virus as Kemin; they all killed more than 2 log10 of virus (>99% inactivation) but it took them 21 days to do so. Ultrap, ADA, and AB were not able to achieve this level of virus kill even after 21 days. Another objective of this study was to evaluate the currently used methods of virus elution from feed and from stainless steel surfaces. Both of the currently used methods were found to be adequate in recovering PEDV. The last objective was to determine the MID50 of a standardized PEDV inoculum. We found that as low as 7 infectious units (TCID50) of cell culture grown virus was able to induce disease in 11-day-old piglets.