As shown in the figure, the response of serpina1 was obvious in the head kidney, kidney, intestine, and gill, with peak expression on day 2 after infection (506.5-fold, 41.8-fold, 195.2-fold, and 296.2-fold, respectively; p < 0.05), and then gradually decreased and returned to normal levels by day 14. This evidence concerns the gene SERPINA1 and infection.