Excessive selenium (Se) intake is harmful for animals and humans. The aim of the present study was to examine the effect of long-term excessive Se supplementation on oxidative stress and endoplasmic reticulum(ER) stress-related injuries in chicken spleen. A total of 180 1-day-old chickens were randomly divided into four groups with different Se dietary contents (0.2 mg/kg Se, 5 mg/kg Se, 10 mg/kg Se, or 15 mg/kg Se) for 45 days. Then, the levels of antioxidative enzymes, GPx, SOD, and MDA as well as the expression levels of GRP78, ARF6, caspase 3, caspase 12, and Bcl 2 in the spleen were determined at days 15, 30, and 45, respectively. The results showed that excessive Se treatment decreased the activities of GPx and SOD (P<0.05) but increased the levels of MDA (P<0.05) in a dose- and time-dependent manner. In addition, the ER stress genes GRP78 and ATF6 were highly expressed (P<0.05), and the apoptosis genes caspase 3 and caspase 12 were increased, but Bcl 2 was decreased by Se treatment (P<0.05). Correlation analysis showed that there was a high correlation between these biomarkers, which indicated that ER stress and ER stress-related apoptosis were correlated with oxidative stress. These results showed the important role of oxidative stress and ER stress in Se-related immune injuries in chicken.
