LAUSR

Selenium (Se) is an essential element for pigs with diet being the major source of intake, while the metabolic process of different sources and doses of dietary Se in pigs muscle remains unclear. In this study, a reliable HPLC-ICP-MS approach was developed for analyzing selenium speciation in the muscle of pigs, which could analyze seven selenium speciation in ten minutes. This approach was used to study the metabolism of different sources and doses of dietary selenium in pigs muscle. In total, 108 castrated male pigs (Duroc × Landrace × Yorkshire, 61.3 ± 3.3 kg) were randomly assigned to six treatment groups with six replicates of three pigs per replicate. These six treatments received the same basal diet (0.1 mg Se/kg) without any Se supplement (BD-0.1), or basal diet supplemented with sodium selenite (0.25 mg Se/kg, SSe-0.25), methylselenocysteine (0.25 mg Se/kg, MeSeCys-0.25), or selenomethionine (0.25, 0.50, and 2.5 mg Se/kg, SeMet-0.25, SeMet-0.5, and SeMet-2.5) for 60 days. At the end of the experiment, six pigs from each group (one pig per replicate) were slaughtered and the longissimus dorsi muscle was collected for total Se and Se speciation analysis. The results showed that the selenium sources deposition efficiency was ranked as: selenomethionine > methylselenocysteine > selenite, and the muscle selenium content had a dose effect with selenomethionine supplementation (Figure 1). Four species of selenium were detected in the muscles of pigs, and the distribution of these selenium species were greatly affected by the dietary selenium supplementation forms and levels (Figure 2). Selenomethionine (> 70% of total selenium) and selenocystine (> 11%) were the major selenium species, followed by methylselenocysteine and selenourea. These findings could be advantageous for rational use of selenium supplements, as well as for selenium-enriched pork production.