TNF and infection: In this study, WUCI exhibited a delayed inflammatory response to A. hydrophila infection compared to WT, and the peak levels of TNF-α, IL-1 β, IL-10, and TGF-β mRNA were lower than those of WT, indicating that although WUCI had a certain degree of resistance to A. hydrophila infection, its overall immune response was inferior to that of WT, making it more susceptible to infection or more difficult to control infection effectively.