Alterations in the Gill Filaments and Secondary Lamellae of Cirrhinus mrigala Exposed to “Nuvan,” an Organophosphorus Insecticide

Figure 3

Photomicrographs of cross-sections of gills of C. mrigala exposed of “Nuvan” for 4 d and then transferred to freshwater for recovery to 15 mg/L (a–c) and to 5 mg/L (d) (H/E). Scale bar = 20 μm. (a) Epithelial cells of the epithelia of secondary lamellae (arrow heads) and gill filament (arrows) appear hypertrophied. Major portion of secondary lamellae is not merged with the epithelium of gill filament. Note secondary lamellae appear thick (2 dr). (b) Similar as (a). Epithelium of secondary lamellae at intervals appears detached from the underlying tissues (arrows) (2 dr). (c) Epithelial cells of the epithelia of secondary lamellae (arrows) and gill filament (barred arrows) do not appear hypertrophied. Note secondary lamellae appear slender (6 dr). (d) Epithelial cells of the epithelia of secondary lamellae (arrows) and gill filament (barred arrows) do not appear hypertrophied. Note secondary lamellae appear slender, similar to those of the controls (4 dr).

(a)

(b)

(c)

(d)