Fig. 1

Soybean meal triggers neutrophil migration to the intestine after two days of feeding.

Tg(mpx:GFP) transgenic larvae were analyzed in vivo by confocal microscopy to monitor neutrophil infiltration into the intestine at day 0 (A–C), 2 (E–G) and 4 (I–K) of feeding with control (pellet) and experimental diets (100FM diet and50SBM diet). (D, H, L) The number of intestine-infiltrated neutrophils was quantified by immunohistochemistry in the same larvae analyzed by confocal microscopy (inset). The results indicated that fish meal did not activate the immune response after 2 or 4 days of feeding. In the case of soybean meal, the number of infiltrated neutrophils was increased from day 2. Five larvae per condition in three different experiments were analyzed per time point by confocal microscopy. For immunohistochemistry analysis, at least 15 larvae per condition per time point in three different experiments were performed. Statistical analysis was conducted using one-way ANOVA. **p value < 0.01; ***pvalue < 0.001.