Avian selenogenome: response to dietary Se and vitamin E deficiency and supplementation

Selenium (Se) is an essential nutrient for humans and all food-producing animal species. Nutritional deficiencies of Se and (or) vitamin E induce exudative diathesis, nutritional pancreatic atrophy, and nutritional muscular dystrophy in chicks. Although these diseases are presumably associated with the need of Se for the synthesis of the 21st amino acid, selenocysteine (Sec, U) in selenoproteins, metabolic functions of the 25 selenoproteins identified in avian species remain largely unknown. This paper reviews regulations of the whole selenogenome and selected selenoproteins by different concentrations and chemical forms of dietary Se and (or) vitamin E in various affected tissues. The avian selenogenome may be divided into 2 groups: responders and non-responders, based on its response to dietary Se and vitamin E changes. Mechanisms for the gene-, tissue-, and age-dependent responses and the correlation with the stress and cell death signaling are explored. Overall, this review intends to link the novel regulation and function of avian selenogenome to the protection by Se against oxidative insults associated with the classical Se/vitamin E deficiency diseases in chicks.