The results revealed that serum irisin levels in E septicemia mice (11.24 ± 1.33 ng/mL) and SA septicemia mice (4.52 ± 0.87 ng/mL) were significantly lower than those in healthy mice (40.02 ± 1.17 ng/mL), thereby confirming our hypothesis. This evidence concerns the gene FNDC5 and Sepsis.