Acute Toxicity of Tephrosia vogelli on the Early Life Stages of Farmed Clarid (Clarias gariepinus)

Abstract

The study examined the acute toxicity of Tephrosia vogelii ethanolic extract on early life stages of farmed Clarias gariepinus. 160 fingerlings were divided into four groups using a completely randomized design (CRD) in a factorial layout and were exposed to 25, 50 and 100 mg/L of the extract for 24, 48, 72 and 96 hours, respectively while the control animals were kept without any treatment. The percentage mortality rate and acute – lethal toxicity (LC50) were determined for the different periods of exposure. Results obtained revealed that no mortality was recorded in the control group whereas a significant concentration – dependent increase in mortality was observed in the groups of animals treated with the extract of the plant. More so, duration of exposure also affected the mortality rate, as the highest percentage of mortality was observed in groups of animals exposed to the extract for 96 h. The LC50 for the T. vogelii extract for 96 h exposure was 9.36 mg/L with lower and upper confidence limits of 4.04 and 21.68 mg/L, respectively. Conclusively, the findings of the study suggest that T. vogelii extract has acute toxic effect on early life stages of farmed clarid and as such, its use in fishing should be discouraged.