The Protective Role of Selenium in AFB 1 -Induced Tissue Damage and Cell Cycle Arrest in Chicken's Bursa of Fabricius.

Aflatoxin B ₁ (AFB ₁ ) is a naturally occurring secondary metabolites of Aspergillus flavus and Aspergillus parasiticus, and is the most toxic form of aflatoxins. Selenium (Se) with antioxidant and detoxification functions is one of the essential trace elements for human beings and animals. This study aims to evaluate the protective effects of Se on AFB ₁ -induced tissue damage and cell cycle arrest in bursa of Fabricius (BF) of chickens. The results showed that a dietary supplement of 0.4 mg·kg ^-1 Se alleviated the histological lesions induced by AFB ₁ , as demonstrated by decreasing vacuoles and nuclear debris, and relieving oxidative stress. Furthermore, flow cytometry studies showed that a Se supplement protected AFB ₁ -induced G ₂ M phase arrest at 7 days and G ₀ G ₁ phase arrest at 14 and 21 days. Moreover, the mRNA expression results of ATM, Chk2, p53, p21, cdc25, PCNA, cyclin D ₁ , cyclin E ₁ , cyclin B ₃ , CDK6, CDK2, and cdc2 indicated that Se supplement could restore these parameters to be close to those in the control group. It is concluded that a dietary supplement of 0.4 mg kg ^-1 Se could diminish AFB ₁ -induced immune toxicity in chicken's BF by alleviating oxidative damage and cell cycle arrest through an ATM-Chk2-cdc25 route and the ATM-Chk2-p21 pathway.