Figure 4.

Histopathological observation of gills of goldfish infected with Myxobolus ampullicapsulatus. (A) Round cysts attaching to gill filaments contained a large number of spores (red dotted box), some of which released from the cysts and entered the gill tissue through the branchial artery (black triangle). (A1) Control group goldfish, with neatly arranged gill lamellae, showing continuous gill-associated lymphoid tissue (black dotted line and black arrow) formed on the gill arch. (B) The gill-associated lymphoid tissue in Myx group was dilated (black dotted line and black arrow). (C) Partial enlargement (red dotted box) of Figure A, dense spores can be seen. (D) The gill of Myx goldfish showed obvious hyperemia (*) (P value), accompanied by a large number of spores distributed in the afferent branchial artery (yellow dotted line) (E) Total score of gill histopathological score; (E₁–E₄) The histopathological scores for cell hyperaemia, lamellae fusion, cell hyperplasia, and necrotic and detachment of epithelial cells, respectively. Significance: P < 0.05 (*), P < 0.01 (**), P < 0.001 (***). (n=6).