Moreover, the mRNA levels of ChIL-2, ChIFN-γ, ChIL-4, ChIL-10, ChIL-6, and ChIL-17 in spleens of chickens immunized with the four Fiber2-expressing probiotics were significantly higher, which suggests that Th10-, Th2-, and Th17-type responses contribute to the strengthened immunity and resistance to virus infection (Figure 5). The gene discussed is CHI3L2; the disease is viral infectious disease.