The Effect of Malathion Concentration and Exposure Time on Histopathological Changes in the Liver and Gill of Rainbow Trout

Figure 3

Histopathological changes in the gill tissue of rainbow trout exposed to malathion (hematoxylin–eosin staining, 400x magnification). In the control group, there was no abnormal change in the gill, including primary and secondary lamellae and chloride cells (A). At the end of Day 1, the second group (0.025 mg/L) (B) showed distal clubbing (a), the third group (0.05 mg/L) (C) showed aneurysm (b), and secondary lamellae shortening (c), and the fourth group (0.075 mg/L) (D) showed secondary lamellae rupture (d) and secondary lamellae epithelium protrusion (f). At the end of Day 5, the second group (0.025 mg/L) (E) showed lamellae fusion (g) and secondary lamellae curling (h), the third group (0.05 mg/L) (F) showed aneurysm (i) and secondary lamellae curling (j), and the fourth group (0.075 mg/L) (G) showed secondary lamellae epithelium protrusion (l) and distal clubbing (k). At the end of Day 9, the second group (0.025 mg/L) (H) showed aneurysm (m) and secondary lamellae epithelium protrusion (n), the third group (0.05 mg/L) (I) showed secondary lamellae rupture (o) and primary lamellae artery rupture (p), and the fourth group (0.075 mg/L) (J) showed hyperemia and secondary lamellae atrophy (q) and secondary lamellae shortening and secondary lamellae–epithelial separation (r).