Selenium deficiency in deer: The effect of a declining selenium cycle ?

FLUCK, WT; SMITH-FLUECK, JM

Trondheim, Norway

Congreso; XIX Congr. Intern. Union Game Biologist; 1989

Selenium (Se) was discovered as an essential trace element in the mammalian metabolism in 1957. Clinical deficiency in neonatal ruminants is expressed as white muscle disease, reduced rate of growth, decreased immune response and sudden death; in adults decreased reproduction is observed, skeletal muscle degeneration and decreased resistance to stress and disease. The common underlaying biochemical lesion results from oxidative damage to cell components. Se was shown to be the integral part of the enzyme system glutathione peroxidase (GSH-Px; glutathione:H2O2 oxidoreductase, EC 1.11.1.9) which functions in detoxification of oxygen species and organic hydroperoxides. Since the body distribution of glutathione peroxidase varies greatly between species, the pathophysiognomy also varies greatly.    Many geographic areas with low Se levels in the soil and plants result in marginal or deficient status of herbivores. However, consideration of the many interactions of other factors with Se metabolism make it doubtful that a single statement of the Se requirement for any species is valid. The Se requirement would have to be established empirically for a specific site and species.    A biological Se cycle was first described in 1964. Basic features of such a cycle include the presence of organisms which reduce the more oxidized selenicals, which in turn are reoxidized. However, only a few micro organisms have been described capable of oxidizing reduced selenicals. Factors contributing to an apparent decline of Se availability include: i) inherent characteristics of Se chemistry;  ii) soil acidification; iii) soil contamination with heavy metals;  iv) fertilizer effect on plants; v) plant community composition; and vi) the role of fire. Thus, land management practices and air pollution appear to be major factor which can alter the Se cycle.