Effect of nano‐sized, elemental selenium supplement on the proteome of chicken liver
Selenium is one of the essential trace elements for life processes (Köhrle, 2004). The biological significance of Se was recognized only in 1973, as a component of the glutathione peroxidase (GPx). This enzyme has an important role in intracellular defence mechanisms against oxidative damage because it prevents the formation of reactive oxygen species (Rotruck et al., 1973). Glutathione peroxidase is a selenoprotein which protects cells and membranes from oxidative damage by destroying hydrogen peroxide and hydroperoxides (Watanabe et al., 1997). Selenium is an important component of several other selenoproteins with essential biological functions (Van Cauwenbergh et al., 2004). Even though the functional roles of these selenoproteins are not fully understood, there is an increasing evidence that these selenoproteins and other Se‐containing metabolites are important in immune function and reduce the risk of cancer (Tinggi, 2003). Selenium‐enriched food can increase the human selenium status, and optimal selenium intake contributes to human health (Fisinin et al., 2009). The selenium status of chicken has effect on survival, growth performance, resistance to diseases, fertility, shelf life of eggs and hatchability (Pappas et al., 2006; Surai, 2006). Earlier, inorganic selenium compound (sodium selenite) has been incorporated into animal diets, but nowadays organic forms of Se (i.e. selenomethionin, selenocysteine or selenium‐enriched yeast) are preferred (Payne and Southern, 2005). Chen and co‐workers demonstrated that different selenium forms (inorganic and organic) had no clear effect on the production traits of broilers, but influenced the resistance against oxidative stress (Chen et al., 2014).
Oremland et al. (2004) presented a biological way to produce nanospheres elemental selenium by selenium‐reducing anaerobe bacteria. Eszenyi et al. (2011) used lactic acid bacteria to reduce the selenite in toxic concentration into nano‐sized elemental selenium spheres with high purity. This procedure seems to be more effective than chemical synthesis. Materials at the nanometers dimension hold promise for application in medicine and nutrition. Plants and several microorganisms, including bacteria and fungi, can synthesize nanoparticles in their metabolic pathways. Nano‐sized selenium has higher bioavailability and relatively low toxicity compared to other selenium forms (Wang et al., 2007). There is a lack of information about the role of increased Se content of feed on liver proteome; thus, the objective of the present study was to compare liver protein profiles of broilers fed with control diet and feed supplemented with 4.25 mg/kg DM nano‐Se.