Fig. 9

Paraffin sections illustrating distribution of intestinal mast cells in control and infected fish, stained with silver impregnation methods and alcian blue PH2.5/safranin O. The staining demonstrated the mast cells’ sensitivity to the silver dye in the control and infected fish. The stained figures using Alcian Blue pH 2.5 with Safranin were included to verify the distribution of positive cells stained with silver stain. The mast cells, characterized by their blue granules (arrowheads). (A-E) Transverse section of the intestine in control fish exhibited mast cells (arrowheads), had a brown coloration positive to silver dye (A, B, and D). (C and E) the comparative figures B and D confirm mast cells stained with alcian blue pH2.5 and safranin O, where they displayed with a blue stain. (F-I) Transverse section of the intestine of infected fish exhibited mast cells (arrowheads), having a positive brown coloration to silver dye (F and G), (H and I) the comparative figures B and D confirm mast cells stained with alcian blue pH2.5 and safranin O, where they displayed a blue coloration (arrowheads)