European seabass juveniles fed a mushroom-derived additive for 110 days survived a bacterial challenge better than controls. The 1 and 2 percent diets gave the clearest change in immune gene expression and plasma enzyme activity. Disease resistance in aquaculture works on a slow clock, and the 2 and 50 day samples showed nothing at all. Why disease resistance in aquaculture is a feed decision now Global aquaculture production reached 103 million tonnes in 2024, which works out at 53 percent of total aquatic animal production. Marine finfish account for a large share of that figure, and they are grown in pens where one bacterial outbreak can end a production cycle…