Abstract:

【Objective】 Aflatoxin B1 (AFB1) is one of the most potent naturally occurring carcinogens and classified as a group I carcinogen. This study has two objectives: (1) To evaluate the effect of 3, 30, 300 μg?kg-1 BW on DNA damage in hepatic cells in Beijing ducklings at different times after administrated by oral feeding. (2) To study the relationship between the level of DNA damage and concentration of AFB1, time after exposed to AFB1, to provide research model for genotoxicity of AFB1. 【Method】 Ninety-six male Beijing ducklings were randomly divided into 16 groups with 6 ducklings in each one. Each duckling in group 1 was administered orally with 1 mL 25% DMSO solution as control, and low (group 2 to 6), moderate (group 7 to 11), high (group 12 to 16) AFB1 exposure groups were given 1 mL with 0.25, 2.5, 25 μg?mL-1 25% DMSO solution by gavage, respectively. The modified comet assay was performed at 1 h in control group, and at 1, 2, 8, 24, 48 h in AFB1 exposure groups on hepatic cells after AFB1 administration. 【Result】 The results showed that ducklings were sensitive to hepatic DNA damage induced by AFB1, and the level of DNA damage was associated with concentration and time after AFB1 intake. DNA strand breaks reached peak value at 2 h of exposure, and all different doses of AFB1 could induce significantly higher tail length, tail DNA%, tail moment, Olive tail moment than in control group (P＜0.05). With AFB1 concentration increasing, the duration of DNA damage prolonged, and under the condition of the same treatment time, the DNA damage was more serious. 【Conclusion】 From the results, three conclusions were drawn as follows: (1) Ducklings are sensitive to DNA damage in live cells induced by AFB1, and low level (3 μg?kg-1 BW) exposure of AFB1 can induce significantly hepatic DNA damage in ducklings. (2) The level of DNA damage reached the peak at 2 h after a single oral administration of AFB1, and at this time the dose-effect relationship was obvious in this experiment. (3) Duckling is an ideal animal model for study of AFB1 genotoxicity, and comet assay is an useful tool for monitoring the hepatic DNA damage induced by AFB1 in ducklings.

Key words: aflatoxin B1, DNA damage, comet assay, duckling