LTF and infection: Interestingly, although the expression of type I interferon (IFN-α/β) was not up-regulated on the 3rd, 5th and 7th days after infection, some miRNAs were down-regulated on the 5th day, including miR-16b, miR-324-3p, miR-124a-1 and miR-31, etc. ISGs expression was significantly up-regulated, including IFIT2, IFIT3, RSAD2, Mx1, CSF3, and LTF, suggesting that the IFN-α/β production pathway was activated and ISGs protein production was induced by above miRNAs.