Effect of EP on cytokines in piglets infected with PDCoV. Peripheral blood samples of the indicated groups were collected at 5 dpi. The serum concentrations of TNF-α (A) and IFN-γ (B) were determined by ELISA. The relative expressions of IL-1β mRNA (C), IL-6 mRNA (D), IL-12 mRNA (E), TNF-α mRNA (F), IFN-α mRNA (G) and IFN-β mRNA (H) in jejunal and ileal tissues were assessed by RT-qPCR. Data are presented as the mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001.