Effects Of Diet With Low Selenium On The Selenoproteins And Cytokines Expressions In Broiler Immune Organs

Selenium is a kind of nutritionally essential trace elements for organisms norma l physiological activities. Se comes from food intake for animals. Se exerts its biological functions as the form of selenoproteins(Sels) in organisms. Se deficiency can cause oxidant stress and induce different tissue injuries, such as muscle necrosis, pancreas atrophy, and immune or nerve damage. Previous studies suggested that Se deficiency could cause chickens exudative diathesis(ED) and damages in intestinal tract, pancreas, heart, skeletal muscle, and influence the expressions of Sels in them. The immune organs(thymus, spleen, bursa of Fabricius) are the targets of Se deficiency as well, and they play important roles in humoral immunity and cellular immunity. So far, the study about the effects of Se deficiency on tissue structure and functions and the expressions of 23 Sels in broilers immune organs has not been reported.In present study, One hundred and fifty broiler chicks were randomly allocated into the control group and low Se group(75 chickens per group). The chickens were maintained either on a diet supplemented with Se through the addition of 0.2 mg/kg Se(C group) via sodium selenite or on a Se deficient deficiency diet(L group, from the Se-deficient region of Heilongjiang Province in China, containing 0.008 mg/kg Se) until the broiler chicks exhibited ED onset. Feed and tap water were supplied ad libitum. In this study, when the symptoms of Se deficiency occurred in the L group at 20 days, the samples were collected. To find the pathologic changes in immune organs caused by Se deficiency, H.E dye and microscopy was using to observe. And by quantitative real-time PCR, the effects of Se deficiency induced by low Se diet on the expression levels of 23 kinds of Sels and cytokines in broilers immune organs were investigated. Finally, Statistical analysis of all of the data was using to research the effects and the mechanisms of Se deficiency on thymus, spleen, brusa of Fabricius in broilers. The results of this study indicated that: 1) Diet with low Se can cause structure changes in the broilers immune organs, it suggests Secan injure the biological functions of broilers immune organs.2) Diet with low Se can induce the mRNA expression levels of 23 Sels decreasing in broilers immune organs, it shows that feeding low Se diet can directly influence th e expressions of Sels in broilers immune organs, and among them, the mRNA levels of antioxidant Sels are affected by diet with low Se more seriously.3) Se deficiency can change the secretions of cytokines in broilers immune organs, it reminds Se deficiency may induce the immune functions reduction in broilers.