The Importance of Pyridoxine for the Impact of the Dietary Selenium Sources on Redox Balance, Embryo Development, and Reproductive Performance in Gilts

This study aimed to determine the effects of dietary pyridoxine and selenium (Se) on embryo development, reproductive performance and redox system in gilts. Eighty-four gilts were fed one of five diets: CONT) basal diet; MSeB60) CONT+0.3mg/kg of Na-selenite; MSeB610) diet 2+10mg/kg of HCl-pyridoxine; OSeB60) CONT+0.3mg/kg of Se-enriched yeast; and OSeB610) diet 4+10mg/kg of HCl-pyridoxine. Blood samples were collected for long-term (each estrus and slaughter) and peri-estrus (fourth estrus d -4 to d +3) profiles. At slaughter (gestation d 30), organs and embryos were collected. For long-term and peri-estrus profiles, Se level and source affected (P<0.01) blood Se concentration whereas B6 level increased (P<0.01) erythrocyte pyridoxal-5-phosphate concentration. A B6 level (P<0.05) effect was observed on long-term plasma Se-dependent glutathione peroxidase (Se-GPX) activity whereas peri-estrus Se-GPX was minimum on d -1 (P<0.01). Selenium level increased sows' organs and embryo Se concentration (P<0.01). Selenium source tended to enhance embryo Se content (P=0.06). Within-litter embryo Se content was increased by B6 level (P<0.01). Selenium level tended to affect Se-GPX and total GPX activities in organs mitochondria (P=0.09 and 0.07, respectively). Selenium source affected kidney ATP synthesis (P=0.05). In conclusion, B6 level affected the Se-GPX activity on a long-term basis, whereas the basal level of Se was adequate during the peri-estrus period. Embryo quality was not improved by dietary Se, and B6 impaired within-litter homogeneity.