Fig. 2
Histological changes of the gill of black porgy Acanthopagrus schlegeli in the control (CS no ozone) and ozonated systems (T20: 20 g ozone/kg feed day−1 and T40: 40 g ozone/kg feed day−1) after 44 days of culture. a Control (CS). Note the gill filament (Gf), gill lamellae (Gl). b T20 group. Hematoxylin and eosin (H&E) section showing the extensive edema of epithelial cells and hypertrophy and clubbed type of gill lamellae. c T20 and T40 groups. Note the hypertrophy, hyperplasia, and fusion of gill lamellae. d T40 group. H&E section showing the epithelial cell lifting (arrow) and the necrosis of gill lamellae