2-Hydroxy-4-Methylselenobutanoic Acid Exerted a Unique Regulation of Selenogenome, Selenoproteins, and Selenocystenine-Related Genes in Tissues of Broiler Chicks

A new organic Se compound, 2-hydroxy-4-methylselenobutanoic acid (SeO), was shown to be more bioavailable than Na₂SeO₃ or seleno-yeast (SeY) to chicks, hens, and pigs. This study was to determine regulations of 26 selenoprotein genes, 5 selenoproteins (GPX1, GPX4, SELENOP, SELENOW, and SELENOU), and 5 selenocystenine biosynthesis and degradation-related genes (Pstk, SeciSbp2, Sephs1, SepSecS, and Scly) by the three sources of Se in liver, breast, thigh, and/or plasma of chicks. Day-old male broilers (n = 6 cages/diet, 6 chicks/cage) were fed a Se deficient, corn/soy-based diet (BD, 0.05 mg Se/kg) or the BD supplemented with Na₂SeO₃, SeY, or SeO at 0.2 mg Se/kg for 6 weeks. Growth performance was recorded weekly, and blood and tissue samples were collected from 6 chicks/group for analyses at the end of study. Data were analyzed using one-way ANOVA. The three sources of Se produced no significant differences in the growth performance compared with the BD control. While all sources of Se enhanced (P < 0.05) mRNA levels of Gpx1, Gpx3, Selenop, Pstk, and SepSecS in the three tissues over the BD group, only SeO upregulated (P < 0.05) the expression of Selenos and Mrsb1 in the liver and thigh. Compared with Na₂SeO₃, SeO caused greater increases (P < 0.05) in expression of Gpx3 mRNA and GPX4, SELENOU, and SELENOP proteins in the three tissues and/or plasma. A greater (P < 0.05) expression of GPX4 and SELENOP protein in the three tissues and/or plasma and Selenop and SepSecS mRNA in the two muscles was produced by SeO than SeY. In conclusion, SeO exhibited a unique ability to induce the expression of Selenos and Mrsb1 mRNA and to enhance the production of GPX4 and SEPP1 proteins in the chick tissues (supported in part by NSFC 31501987 and 31320103920, NSTSPC-2013BAD20B04, and Adisseo).