Abstract
This research was undertaken to study the toxic effects of low level aflatoxin B1 (AFB1) on hepatic enzyme activities and white blood cell parameters in fresh water fish Nile tilapia (Oreochromis niloticus). Two hundred and seventy fresh water fish Nile tilapia, 2 months old, were acclimated for 7 days and then entered into an experiment with a completely randomized design. They were divided by weight into three groups of 30 fish per group and tested in triplicate. They were fed commercial feed, which was confirmed to be free from AFBI through analysis by ELISA. One of the three groups was orally intubated and given a single dose of olive oil, as a control. The other groups were orally intubated and given a single dose of 20 or 40 μg/kg body weight (bw) AFB1.On the 1st, 2nd, 42th, 8th, 10th, 16th, 20th, 24th, 30th and 48th hour of the experiment, nine fish of each group (three fish of each replication) were randomly selected. Blood was collected from the caudal vessel and monocyte, lymphocyte and neutrophil counts were determined. Glutamic oxaloacetic transaminase (GOT), gutamic pyruvic transaminase (GPT), alkaline phosphatase (ALP) and gamma glutamyltransferase (GGT) were measured in serum samples. On the 1st and 2nd hour of the experiment, average cell counts of monocytes and lymphocytes were significantly higher in the AFB1-treated groups than in the control group, whereas neutrophil counts were significantly lower in the AFB1-treated groups than in the control group. After the 4th hour of the experiment, the results showed the same pattern and there were significant differences between the 20 μg/kg bw AFB1 group and the 40 μg/kg bw AFB1 group. GOT, GPT, ALP and GGT levels were significantly increased in the AFB1-treated groups, in comparison to the control group. Results of this study show that the hepatic enzyme activity and the white blood cell counts are a potential indicator for low level AFB1 intoxication.
