Toxicity Effects of Brown Dried Pawpaw (Carica papaya) Leaf Extract to Fingerlings of African Catfish Clarias gariepinus

Abstract

The acute and sub-lethal bioassay of aqueous extract of fresh pawpaw (Carica papaya) leaf on Clarias gariepinus fingerlings was investigated. The experiment was carried out at Department of Fisheries Teaching and Research Fish Farm, Modibbo Adama University of Technology Yola. At 96h static bioassay, symptoms of toxicity in the fish indicated that aqueous extract of fresh pawpaw leaf caused sub-acute effects such as altering fish behavior. These behaviors include air gulping, erratic swimming, discoloration, loss of reflex and skin peeling. These behavioral alterations were time and concentration dependent. Exposure to aqueous extract of fresh pawpaw leaf caused decrease in packed cells volume (PCV), haemoglobin (Hb), and red blood cell (RBC), mean corpuscular haemoglobin concentration (MCHC) and an increase in the mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV). It resulted in marked increase in white blood cells (WBC). Mortalities and LC50-96h values for Clarias gariepinus exposed to fresh pawpaw leaf extract was (10.9 ml/l). The mortality rates in extracts to Clarias gariepinus in sub-lethal exposure was lower than in acute concentrations. The growth rates were significantly reduced in fish exposed to sub-lethal concentrations of the fresh pawpaw leaf extract compared to the control fish (p<0.05).