Effects of dietary mixed aflatoxin B1 and fumonisin B1 on growth performance and haematology of juvenile Clarias gariepinus catfish

Abstract

This study aimed to determine the effects of dietary mixtures of aflatoxin B1 (AFB1) and fumonisin B1 (FB1) on growth performance and haematology of juvenile Clarias gariepinus and also determine the maximum tolerable limits for the mixture of these mycotoxins in C. gariepinus. Five experimental diets amended with varied concentrations of AFB1 and FB1 (Diet A (control 2.0 μg AFB1; 3.0 mg FB1/kg); Diet B (7.3 μg AFB1; 15.0 mg FB1/kg); Diet C (17.6 μg AFB1; 24.5 mg FB1/kg); Diet D (48.0 μg AFB1; 43.0 mg FB1/kg) and Diet E (93.0 μg AFB1; 83.0 mg FB1/kg were fed to 450 juvenile C. gariepinus catfish in five groups of 15 separate plastic tanks for a period or 56 days. Five fish were randomly sampled from each tank at time points day 7, 14, 28 and day 56. These fish were weighed, length measured and bleed for haematological determinations. Fish fed the diets amended with mixtures of AFB1 and FB1 exhibited significant reduction (p < 0.05) in growth performance marked by reduction in mean length gain; mean weight gain and specific growth rate compared to fish fed the control diets. Further, fish fed diets amended with mixtures of the mycotoxins showed significant reduction (p < .05) in the erythrocytes count, haemoglobin concentration and haematocrit compared to fish fed the control diet. Based on the results of growth and haematological performance, juvenile C. gariepinus can tolerate diets containing up to 17.6 μg AFB1/kg and 24.5 mg FB1/kg.