Effects of selenoprotein W and selenium-binding protein 1 on the transformation of skeletal muscle fibre types in pigs

The aim of the current study was to analyze the expression of selenoprotein W (SELW) and selenium-binding protein 1 (SBP1) in the skeletal muscle of pigs during growth and development and their effects on the gene expression of muscle fibre type. We first assessed the expression of SELW, SBP1 and myosin heavy chains (MYHC I, IIA, IIX and IIB) at days 7, 35, 45, 85 and 180. We subsequently established SELW/SBP1 overexpression and interference models and conducted in vivo trials with basal diets supplemented with 0, 0.3, 1, 3 or 5 mg/kg yeast selenium. The expression level of SELW increased with age (p < 0.05), and SBP1 expression was higher during the suckling compared to the growth and fattening periods (p < 0.05); both Spearman correlation analysis and in vitro experiments demonstrated a positive correlation between the expression levels of SELW and MyHC IIB. Increasing dietary selenium induced a quadratic trend in SELW and SBP1 mRNA and protein expression, which was optimal at 1 mg/kg (p < 0.05). Overall, this study not only elucidates the distinct roles of SELW and SBP1 in muscle fibre type but also provides a theoretical basis for enhancing pork quality via dietary selenium intervention.