Effects of glucuronic acid and N-acetyl-D-glucosamine supplementation on the perivitelline space during the IVM of pig oocytes.

The objective of this study was to minimise polyspermic penetration by increasing the perivitelline space (PVS) thickness through supplementation of the hyaluronic acid components glucuronic acid and N-acetyl-d-glucosamine (GlcNAc). Oocytes (n = 4690) were supplemented during the first 24 h and/or the remainder of maturation (final 16–18 h) with 0.01 mM glucuronic acid and 0.01 mM GlcNAc and then evaluated for PVS thickness, hyaluronic acid, glutathione and glutathione peroxidase concentrations. Fertilised oocytes were evaluated for polyspermic penetration and embryo development. The PVS thickness and amount of hyaluronic acid was significantly (P < 0.05) greater in oocytes supplemented with 0.01 mM glucuronic acid and 0.01 mM GlcNAc during the second part or all of maturation compared with the other treatments. In addition, polyspermic penetration was significantly (P < 0.05) less in oocytes supplemented with 0.01 mM glucuronic acid and 0.01 mM GlcNAc during the second part or all of maturation compared with the other treatments. Supplementing 0.01 mM glucuronic acid and GlcNAc during maturation significantly (P < 0.05) increased the percentage of cleaved embryos by 48 h after IVF and blastocysts formed by 144 h after IVF compared those not supplemented. These results indicate that supplementing PVS components during maturation decreases polyspermic penetration by increasing PVS thickness.