Abnormalities in behavioral responses and hematological parameters of African catfish Clarias gariepinus juveniles exposed to acute and sub-chronic effects of mancozeb

Abstract

The present study investigated the effects of acute and sub-chronic exposure to Mancozeb on behavioral responses and haematological parameters of Clarias gariepinus juveniles. A total of 120 Clarias gariepinus with standard length and weight which ranged from 9.8 cm to 17.5 cm and 11g to 55 g respectively were used for the experiment. Prior to the experiment, determination of median lethal concentration. LC24-96h of Mancozeb, a total of 150 Clarias gariepinus juviniles were used. They were exposed to five treatments: 0.00, 150, 300, 450, 600 and 750 mg/L (A-E). While, during sub-lethal determination four treatments were exposed to 0.00. 20.55, 41.09 and 82.18 mg/L (A-D). Each group were replicated three times. Acute toxicity was carried out and the percentage mortality and survival were recorded. The 96 hours LC50 value of Mancozeb on Clarias gariepinus juveniles was estimated to be 410.90 mg/L. The physico-chemical parameters of water observed for five weeks showed changes and fluctuations in temperature range from 28 °C to 32 °C, pH levels ranged from 7.3 to12.3, Alkalinity range 0.88 to 4.10 mg/L, CO2 values ranged from 3-12.5 mg/L. While dissolved oxygen from 6.6 to 7.8 mg/L. Behavioral changes observed after 24-96 hours of fish exposure to different concentrations of Mancozeb revealed loss of equilibrium status and respiratory difficulties. The estimated safe levels varied from 41.09– 4.109 ×10-3 mg/L. Erythrocytes were sampled to investigate haematological parameters. The results showed significant concentration and duration-dependent decrease in RBC count, PCV, Hb and increased in WBC while MCH was not significantly different while MCHC and MCV fluctuated. The activities of neutrophils and lymphocytes were not significantly different among treatment groups whereas Monocytes, Basophiles and Eosinophiles fluctuated.