In contrast, the expression levels of TNF-α (P = 0.039), IL-22 (P = 0.033) and IL-6 (P = 0.016) in jejunal mucosa at 12 h and IL-22 (P = 0.030) expression in ileal mucosa at 72 h post infection, were markedly upregulated in nonspecific yolk powder group (Fig. 4 a, c, d and e). Here, IL22 is linked to infection.