Effect of feeds on histopathology of gills, skin, liver and kidneys of Clarias gariepinus (Burchell, 1822) reared in plastic tanks

The aim of this study was to assess histopathological alterations in the gills, skin, liver, and kidneys of the African catfish (Clarias gariepinus) fed with industrially manufactured extruded (Le), locally pelleted (Lpe) and locally extruded (Lex) feeds and reared in intermediate bulk containers (IBC) tanks. Nine hundred juveniles (15.15± 3.48 g; 128.37± 9.67 mm) were stocked in 9 IBC tanks (1 m³) at a density of 100 fish/tank in triplicate and fed with the studied feeds thrice a day to satiation for 16 weeks. At the end of the experiment, 5 fish/treatment were harvested and the studied organs were extracted for histopathological assessment using standard procedures. Results revealed that no pathological alterations were observed in the gills, skin, liver, and kidneys of fish fed with “Le” feed. Hyperplasia of interlamellar epithelia, fusion of lamellae, curling of secondary lamellae, edema of primary lamellae, and erosion of secondary lamellae were observed in the gills of fish fed with “Lpe” and “Lex” feeds. Skin tissues indicated the presence of mucous cell proliferation and hypertrophy, erosion of epithelial surfaces, and thickening of the epidermal layer in fish fed with “Lpe” and “Lex” feeds. Mild diffuse and moderate vacuolation of hepatocytes were observed in the liver of fish fed with “Lpe” and “Lex” feeds respectively. Moderate diffuse vacuolar degeneration of the epithelial cells of the tubules with mild fatty change was observed in the kidneys of fish fed with “Lpe” and “Lex” feeds. The lesions observed in the local feeds were categorized as mild to moderate and could be reversible indicating that these feeds could be used in out-of-pond holding systems.