As an essential trace element, selenium (Se) is
important for animal and human health. Se deficiency
causes cardiac and muscular degeneration, such as
White Muscle Disease (WMD) in livestock and
Keshan disease in humans (Schubert et al. 1961;
Chen et al. 1980) and selenium supplementation
reverses muscle weakness in Se-deficient humans and
animals (Brown et al. 1986; Chariot and Bignani2003). Se protects against gizzard myopathy and
skeletal muscle degeneration, and increases reproductive
performance in poultry (Walter and Jensen
1963; Cantor et al. 1978; Ebeid 2009). In addition,
the recent report indicated that Se deficiency in the
chicken impaired thymus function (Peng et al. 2010),
thus Se supplementation is necessary for poultry
growth performance.