Table 4.
Influence of processed porcine epidemic diarrhea virus (PEDV)–inoculated feed on quantitative reverse transcription PCR cycle threshold (Ct) of feed, fecal swabs, and cecum contents of pigs, Exp. 21
| Fecal swabs, Ct | |||||||
|---|---|---|---|---|---|---|---|
| Item | KSU2 feed inoculum, Ct | 0 dpi3 | 2 dpi | 4 dpi | 6 dpi | 7 dpi | 7 dpi cecum content, Ct |
| Processed feed, % positive4 | |||||||
| Negative | –5 | – | – | – | – | – | – |
| 37.8°C | 100.0 (9/9) | – | (1/9) | (3/9) | (3/9) | (3/9) | (3/9) |
| 46.1°C | 100.0 (9/9) | – | (3/9) | (3/9) | (3/9) | (3/9) | (3/9) |
| 54.4°C | 100.0 (9/9) | – | – | – | – | – | – |
| 62.8°C | 88.9 (8/9) | – | – | – | – | – | – |
| 71.1°C | 88.9 (8/9) | – | – | – | – | – | – |
| Processed feed, Ct values6 | |||||||
| Negative | – | – | – | – | – | – | – |
| 37.8°C | 32.5a | – | 15.8 | 27.5 | 16.6 | 17.8 | 16.9 |
| 46.1°C | 34.6b | – | 24.5 | 15.2 | 15.4 | 17.9 | 18.8 |
| 54.4°C | 37.0c | – | – | – | – | – | – |
| 62.8°C | 36.5c | – | – | – | – | – | – |
| 71.1°C | 36.7c | – | – | – | – | – | – |
a–cMeans within a column with different superscripts differ (P < 0.05).
1500 mL of tissue culture containing 4.5 · 106 tissue culture infectious dose [TCID]50 (the concentration used to see cytopathic effect in 50% of the cells)/mL of PEDV was inoculated into a 4.5 kg batch of feed and then added to 45 kg of PEDV-negative feed to form the positive treatment. One feed sample per temperature per replicate · 3 replicates was collected, divided into 3 aliquots, and diluted in PBS to form supernatants. Therefore, each feed supernatant value per treatment represents the mean of 3 replicates · 3 repetitions.
2KSU = Kansas State University (Manhattan, KS).
3dpi = days after inoculation.
4Means represent the percent of samples that had detectible RNA by PEDV quantitative reverse transcription PCR analysis (<45 Ct).
5No detectible PEDV RNA (Ct >45).
6Mean Ct value of samples with detectible PEDV RNA below 45.