Lack of Dose- and Time-Dependent Effects of Aflatoxin B1 on Gene Expression and Enzymes Associated with Lipid Peroxidation and the Glutathione Redox System in Chicken

Effects of aflatoxin B1 (AFB1) on lipid peroxidation and glutathione system were investigated in chicken liver. In a three-week feeding trial, different doses (<1.0 mu g/kg (control diet), 17.0 mu g (diet A1), 92.0 mu g (diet A2), and 182.0 mu g (diet A3) AFB1 kg/feed) were used. Markers of lipid peroxidation, conjugated dienes and trienes showed higher values in A3, while amounts of thiobarbituric acid reactive substances were increased in the A1 group at day 21. Glutathione content was lower at day 14 in Group A2. Glutathione peroxidase 4 activity was increased at days 7 and 21 in the A3 group but reduced in the A2 and A3 groups at day 14. The GPX4 gene was downregulated at day 7 in the A2 group, but overregulated at days 14 and 21, and at day 14 in the A3 group. GSS was downregulated at day 14 in the A1 group but overregulated at day 21 in A1 and A2 groups. GSR was downregulated at days 7 and 21 in all treatment groups, but on day 14, induction was observed in the A3 group. The results indicated that AFB1 did not induce dose- or time-dependent effects on the glutathione redox system and its encoding genes at the dose range used, which means that oxidative stress is not the primary effect of AFB1 toxicity.