The current study aimed to investigate the interactions between blood immune parameters (phagocytic activity, serum lysozyme) and the mRNA expression of immune-related genes (TNF-α, IL1β, IL-10, and IgM) and their protective effect on Nile tilapia in response to A. hydrophila infection and also to indicate the immunomodulatory effect of M. oleifera regarding the release of both pro-and anti-inflammatory cytokines in fish post infection in order to evaluate its potential in protection against systemic inflammatory response syndrome (SIRS) and septic shock caused by virulent A. hydrophila. Here, LYZ is linked to infection.