Unlike our in vitro results, expression levels of duIL-23p19 mRNA were unchanged at the early time points (4, 8, 12, and 24 h) of R. anatipestifer infection in ducks, although the expression levels were higher slightly by 1.7- and 2.4-fold at days 4 and 7 post-infection, whereas IL-17A mRNA expression levels were upregulated at all time points. Here, IL17A is linked to infection.