Impact of Annona muricata Ethanolic Leaves Extract on Behavioural Responses and Histopathology of the Gills and Liver of African Catfish (Claria gariepinus, Burchell 1822) Fingerlings

Abstract

This study evaluated behavioural responses and histopathological changes in the gills and liver of African catfish (Clarias gariepinus) fingerlings exposed to ethanolic leaf extract of Annona muricata to understand its toxic effects. Fish were exposed to graded concentrations (0, 2, 4, 6 and 8.0 mg/L) for 96 h, and time-dependent lethal concentrations were monitored. Behavioral abnormalities and tissue alterations were assessed. The 96-h LC₅₀ was 1.38 mg/L (log concentration 0.14 mg/L), indicating moderate acute toxicity. Alterations in water quality were also observed in a concentration- and time-dependent manner. Prominent behavioural aberrations included excessive mucus secretion, air gulping, respiratory distress, erratic swimming, and vertical positioning. Histopathological lesions in the gills comprised hyperplasia, epithelial erosion, lamellar fusion, and cellular degeneration, while hepatic lesions included coagulative necrosis, vacuolation, hyperplasia, necrotic hepatocytes, and hepatopancreatic tissue lysis. These effects may be linked to phytochemicals present in A. muricata which might have resulted in the observed histopathogical changes. The need for safe inclusion limits is strongly recommended to ensure aquaculture productivity and food safety. The study underscores the importance of proper dosage assessment when considering plant extracts for aquaculture applications.