Title: Comparative oral dose toxicokinetics of selenium compounds commonly found in selenium accumulator plants
Authors: Davis TZ, Stegelmeier BL, Welch KD, Pfister JA, Panter KE, Hall JO
Journal: J Anim Sci
Accepted date: 2013 Apr 2
Interpretive summary: Selenium (Se) is an essential trace element that is required for many physiological processes. Selenium deficiency is a common problem in many states in the western United States, but it can also be toxic. Since the difference between deficiency and toxicosis is very small, cases of both acute and chronic Se toxicosis are not uncommon. Acute selenosis can be caused by misformulated supplements misformulated feed mixes, or grazing Se-accumulator plants on seleniferous soils. Consumption of Se accumulator plants by livestock can result in Se intoxication. Recent research indicates that the Se forms most common in Se accumulator plants are selenate and Se-methylselenocysteine (MeSeCys). The storage of Se in a chemical form other than SeMet, allows the plant to grow on seleniferous soils and store up to several thousand parts per million (ppm) Se without adverse effects to the plant. In this study the absorption, distribution, and elimination kinetics of Se in serum and whole blood of lambs dosed with a single oral dose of sodium selenate or MeSeCys were determined. The results demonstrate that there are significant differences between the kinetics of different selenocompounds when orally dosed to sheep. Therefore, in cases of acute selenosis it is important to understand the chemical form to which an intoxicated animal was exposed when determining the significance and meaning of Se concentration in serum or whole blood obtained at various times post-exposure. This study also highlights the facts that differing chemical forms of Se are likely absorbed in different parts of the gastrointestinal system by different routes. This certainly alters all aspects of Se kinetics including absorption, distribution and elimination. With the results of this study, one should recognize that other chemical forms of Se likely also have their own unique toxicokinetic characteristics.
Publication date: 2013 Sep