Investigations on the Potential of Indian Almond Tree (<i>Terminalia catappa</i>) Leaf Extracts as Anaesthetic Agent in African Catfish (<i>Clarias gariepinus</i>)

Abstract

Potentials of Indian almond tree leaf (Terminalia catappa) as anaesthetic agent in African catfish (Clarias gariepinus) were investigated. Juvenile (mean length 26.64 cm ± 3.11SD; mean weight 356.21 g ±12.91SD) and adult fish (mean length 52.13 cm ± 12.91SD; mean weight 1100.30 g ± 41.61SD) were exposed to the aqueous extracts of the T. catappa leaves at five concentrations 0.00 ml/L (control), 50.00 ml/L, 100.00 ml/L, 150.00 ml/L and 200.00 ml/L. The results obtained indicated that the leaf extracts have no effects on the water quality variables such as temperature, pH, nitrate, ammonia and sulphide, with the exception of dissolved oxygen which reduced significantly (P<0.05) from 7.00 mg/L to 3.59 mg/L at 200.00 m/L of the extracts. The induction time (time taken for the fish to get anaesthetized) reduced considerably as the concentration of the plant extracts increased, while the reduction time (time taken for the fish to resume active swimming) increased concurrently with the increase in the concentration of plant extracts. The survival rates of both sizes were low at higher concentration 150 m/L and 200 m/L of the extracts. The results indicated that extracts of India almond tree leaf could induce anaesthesia in C. gariepinus and therefore can be considered as potential anaesthetic agents for use in aquaculture.

Key Words: Anaesthetics, plant, fish, aquaculture, size