Figure 6.

Viral shedding of directly challenged transgenic chickens. Twenty three-week-old non-transgenic chickens (non-TG) and transgenic chickens (D-280) were housed each containment cages in a BSL2 animal facility, and an additional twenty three-week-old SPF chickens were housed as a control group. Ten chickens from each group were intranasally challenged with 100 $\mathrm{\mu }\mathrm{l}$ of 10^7.5 EID₅₀/mL H9N2 virus. The other 10 naïve chickens in each group were co-housed in the same containment isolator from 6 hour post-inoculation. Oropharyngeal and cloacal swab samples were collected at 3, 5, 7, and 9 days post-inoculation (dpi) from the challenged chickens and the viral RNA was quantified by real-time RT-PCR. Each cycle threshold value was extrapolated to egg infectious dose fifty and mean viral shedding titers were calculated. ***p < 0.001 by unpaired t-test.