To validate the contributing role of the TCA cycle in the fish survival upon infection, the activity of three key enzymes in the central carbon metabolism of zebrafish was measured, including PDH that transforms pyruvate into acetyl-CoA, KGDH that converts α-ketoglutarate to succinyl-CoA, and SDH that catalyzes the oxidation of succinate to fumarate. This evidence concerns the gene PDP1 and infection.