Selenium Deficiency Influences the mRNA Expression of Selenoproteins and Cytokines in Chicken Erythrocytes

Selenium (Se) deficiency induces hemolysis in chickens, but the molecular mechanism for this effect remains unclear. Se primarily elicits its function through the activity of selenoproteins, which contain the unique amino acid selenocysteine (Sec). In this study, we aimed to investigate the effect of Se deficiency on the expression of 24 selenoproteins and 10 cytokines. One hundred eighty chickens were randomly divided into 2 groups (90 chickens per group). During the entire experimental period, chickens were allowed ad libitum consumption of feed and water. The chickens were fed either a Se-deficient diet (0.008 mg Se/kg; produced in the Se-deficient area of Heilongjiang, China) or a Se-supplemented diet (as sodium selenite) at 0.2 mg/kg for 35 days. At the 35th day, the messenger RNA (mRNA) levels of 24 selenoproteins and 10 cytokines were examined in erythrocytes of 5 chickens per group, and the correlation was analyzed. The results showed that the expression of 24 selenoproteins and 7 cytokines (IL-2, IL-4, IL-8, IL-10, IL-12β, TGF-β4, and IFN-γ) decreased (P < 0.05), and the expression of 3 cytokines (IL-1γ, IL-6 and IL-7) was higher in the Se-deficient group. In both groups, glutathione peroxidase (GPX), thioredoxin 1 (Txnrd1), selenoprotein P1 (SELP), and selenoprotein synthetase (SPS2) were highly expressed compared to the other selenoproteins in chicken erythrocytes (P < 0.05). These data suggest that GPXs, Txnrd1, SELP, and SPS2 possibly play a more important role than the other selenoproteins. The increase of pro-inflammatory cytokines (IL-1γ, IL-6, and IL-7) suggested that the immune system of chickens was damaged by the Se deficiency. Correlation analysis suggested that although the expression of 24 selenoproteins and 7 cytokines decreased and that of 3 cytokines increased, there was a close correlation between their expression levels and a Se diet. These results suggested that Se deficiency influenced the expressions of 24 selenoproteins and 10 cytokines in chicken erythrocytes, revealing a relationship between Se and the chicken immune system. This study offers information regarding the mechanism of Se deficiency-induced hemolysis.