The importance of pyridoxine for the impact of the dietary selenium sources on redox balance, embryo development, and reproductive performance in gilts

Pyridoxine (Vitamin B6) and the Glutathione Peroxidase System; a Link between One-Carbon Metabolism and Antioxidation

“…Dalto et al [38] reported that, under the oxidative stress of ovulation, the gene expression of GPX1, 3, and 4 in the livers (Table 1) and kidneys (Table 2) of Se-supplemented animals were higher than in the control Se-unsupplemented group, and animals supplemented with organic Se plus B 6 had the highest gene expression of GPX1 and selenocysteine lyase (SCLY), indicating that the transsulfuration pathway was stimulated. In contrast, Dalto et al [39] observed, under basal oxidative stress conditions, no differential expression for the same genes (Table 1 and Table 2). …”

“…Although under marginal B 6 levels, these studies indicate that the B 6 status may not be a determining factor of the transsulfuration pathway flux, which is possibly mainly controlled by ROS and SAM levels. In fact, Dalto et al [39] reported no effect of B 6 on either blood SeGPX activity or GPX and SCLY gene expression in gilts at 30-days of gestation (Table 1 and Table 2), a conditions shown to be of low oxidative stress in this species. These results suggest that under basal oxidative stress conditions, in animals supplemented with Se and B 6 , neither remethylation nor transsulfuration but Se deposition into proteins is the major route for this mineral.…”

“…Recent studies on Se and B 6 metabolisms by this laboratory, using the peri-estrus period as a model for oxidative stress in gilts [38,39,51], provided peculiar information about the control of this metabolic pathway. Although those studies did not specifically address the homeostasis of –CH3 groups, based on the above information this review makes some indirect inferences about the one-carbon metabolism from responses reported in relation to the transsulfuration pathway.…”

“…According to Dalto et al [38,39], B 6 supplementation (10 mg/kg) does not affect the deposition of blood or tissue Se on a long-term basis (3 to 5 estrus), as well as blood Se levels during the peri-estrus period (oxidative stress condition) for both MSe and OSe. For MSe it is not surprising because, independently of the physiological state, absorbed selenite is quickly transformed into selenide and then converted into functional Se-proteins or methylated instead of being actively stored [9].…”

“…Nevertheless, embryos from OSe supplemented dams are richer in Se than those from MSe supplemented dams. It was hypothesized that the most probable source is the pre-ovulatory oocyte that might be affected by the systemic maternal blood Se concentration through follicular fluid, considering that OSe is known to be more common deposited in tissues than is MSe [39,51,57,58]. In fact, Dalto et al [56] observed that maternal supplementation with OSe plus B 6 stimulated 28.8 times more genes than MSe plus B 6 (six and 173 genes for MSe and OSe, respectively).…”