Fig. 1

Light microscope images obtained from the distal intestine of sea bass fed with diet C. a Morphology of a complete section of intestine at low magnification, hematoxylin-eosin staining. b In the epithelial skinfold, at higher magnification, numerous eosinophils vacuoles are visible (white arrowheads). c Alcian blue-PAS staining showing the presence of numerous PAS-positive enterocytes vacuoles (white arrowheads) and a few Alcian blue positive Goblet cells (black arrowheads). d Immunohistochemical analysis showing numerous infiltrating CD45⁺ leukocytes in the lamina propria, submucosa, and muscle layers (black arrows). Bar in a 1 mm; bar in b 50 μm; bars in c, d 100 μm