Table 3.
The efficiency of lactogenic immune protection by oral administration of NH-TA2020.
| Group | Pregnant gilts challenged with | Mean S/P value of IgA | Piglets challenged with | Days post challenge |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | ||||
| A | NH-TA2020 | 8.849 | NH-TA2020 | 6/36 | 14/36 | 17/36 | 16/36 | 9/36 | 8/36 | 3/36 | 0/36 | 0/36 | 0/36 |
| B | DMEM | 0.134 | NH-TA2020 | 25/29 | 28/28 | 20/20 | 11/11 | 5/5 | 4/4 | 3/3 | 1/1 | – | – |
| C | NH-TA2020 | 7.872 | CH–HeB-RY-2020 | 12/35 | 17/35 | 18/35 | 15/35 | 13/35 | 6/35 | 3/35 | 2/35 | 0/35 | 0/35 |
| D | DMEM | 0.238 | CH–HeB-RY-2020 | 27/33 | 29/29 | 18/18 | 11/11 | 3/3 | – | – | – | – | – |
Note: Six pregnant gilts were infected with 2 × 107.0 TCID50 NH-TA2020 viruses orally 60 days before delivery. Another pregnant six gilts were fed with the same dose of DMEM. All the gilts were divided randomly into four groups and each group included three NH-TA2020 viruses challenged gilts (group A and C) or DMEM challenged gilts (group B and D). Anti-PEDV IgA in colostrum samples of each pig was detected using ELISA and the mean S/P values of each group were shown. On the third day after birth, piglets were infected with 106.5 TCID50 NH-TA2020 viruses (group A and B) or CH–HeB-RY-2020 strain tissues (1/10 homogenized intestines per piglet) (group C and D) orally. Numbers of piglets with clinical symptoms were recorded daily including vomiting, diarrhea, and dehydration.