Effect of Nauclea subdita (Korth.) Steud. leaf extract on hematological and histopathological changes in liver and kidney of striped catfish infected by Aeromonas hydrophila.

The present study was conducted to investigate the efficacy of different doses of Bangkal (Nauclea subdita) leaf extract on hematological and histological changes in kidney and liver of catfish (Pangasius hypophthalmus) infected by Aeromonas hydrophila.

Catfish were experimentally infected with A. hydrophila at a dose of 10⁸ cells/mL through intraperitoneal injection, and the hematological and histological changes in the kidney and liver of catfish against the pathogen were observed.

Not all concentrations of N. subdita caused a toxic effect in striped catfish. The clinical symptoms of catfish after infection with A. hydrophila and treatment with N. subdita leaf extract included morphological and behavioral changes. N. subdita leaf extract reduced mortality caused by A. hydrophila. Treatment with N. subdita leaf extract was effective in reducing the inflammation by decreasing the activity of neutrophils, monocytes, and lymphocytes. The Hb and Ht levels of catfish significantly decreased after exposure to 10⁸ cells/mL of A. hydrophila and increased significantly after N. subdita treatment. Necrosis percentages in the kidney and liver also decrease after N. subdita treatment.

The results indicate that N. subdita leaf extract stimulates the immunity and increases the resistance of catfish to A. hydrophila. N. subdita leaf extract may be used as a potential source for future drug development and food applications.