Decreased miR-21 in carp muscle tissue, negatively regulated IRAK4, activated NF-κB pathway, induced inflammation, and led to endoplasmic reticulum stress and apoptosis.Disturbed the detoxification response of mouse liver, promoted oxidation imbalance, increased the expression of inflammatory foci and cytokines, and aggravated liver fibrosis.Reduced the rumen function and the feed utilization efficiency. The gene discussed is IRAK4; the disease is Hepatic fibrosis.