Fig. 6
![Fig. 6](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12917-019-1984-8/MediaObjects/12917_2019_1984_Fig6_HTML.png)
The one-step growth curves of the rescued viruses (including the Positive control, YiY-3-2-3, YiY-3-2-1 and YiY-3-2-10) were performed by determining PCV2 genomic copy number using quantitative real-time PCR. a The content of the intracellular virus; b The content of the extracellular virus. The X-axis shows the incubation time, while the Y-axis indicates the viral load as the logarithm of the copy number of intracellular and extracellular virus. Results were expressed as mean ± SD. This assay was repeated three times. ** and *** represents statistical significance P<0.01 and P<0.001 relative to the YiY-3-2-3 group, respectively