Gene Expression and In Vitro Maturation of Sheep Oocytes using Bee Pollen and Bee Honey as Medium Supplements

Abstract

This study was conducted to investigate the effects of raw honey obtained from black seed or Sider and honeybee pollen as an additive in sheep oocyte maturation medium on the oocyte maturation rate, changes in oocyte glutathione (GSH) levels and expression of developmental candidate genes (GDF-9, MPF, C-MOS, IGF-1, BAX). Healthy immature oocytes of Najdi sheep were cultured in a medium supplemented with 5.0% Sider or Nigella sativa (black seed) honey + 1.0 μg/mL honeybee pollen, and after 24 h of incubation, the effects on the improvement of in vitro oocyte maturation were evaluated. Results demonstrated that the mean oocyte maturation rate was the best in group treated with 5% N. sativa (Group 3) compared with group treated with Sider or N. sativa honey (Group 1A and B, respectively). Mean GSH level was higher in Group 3 oocytes (11.09 ± 0.29 nmol) than in Group 2 oocytes (honey alone; 10.93 ± 0.57; P ≤ 0.05). Mean GSH levels were significantly decreased in Group 1. Expression analysis of candidate genes showed significant upregulation of GDF-9, cyclin B, C-MOS and IGF 1 genes in Group 3 and downregulation of BAX compared with control Group 1. In conclusion, addition of 1.0 μg/mL honeybee pollen along with one of two types of bee honey (Sider and N. sativa) at 5% concentration to the in vitro maturation medium of Najdi sheep oocytes has a beneficial effect in improving the maturation rate and gene expression and increasing the glutathione concentration in matured oocytes. © 2020 Friends Science Publishers