Abstract
Sheep are important livestock and a source of milk, meat, and wool globally. The increasing demand for animal protein requires increased productivity in sheep. In vitro fertilization and maturation can improve sheep productivity. The aims of this study were to evaluate the effects of honey bee addition as a supplementation medium on in vitro maturation improvement, gene expression of matured sheep oocytes, and determine the optimum concentration from honey bee for in vitro maturation of sheep oocytes. Cumulus oocyte complexes were obtained from the ovaries of slaughtered female sheep. Grade A and B oocytes were cultured for 24 h in medium without honey bee (control, G1) or medium supplemented with 5% (G2), 10% (G3), or 20% (G4) honey bee. Oocyte maturation rate, glutathione concentration, and the expression of candidate genes (GDF-9, BAX, Cyclin B, C-MOS, IGF1) were determined in the matured oocytes. The maturation rate of sheep oocyte was better in the presence of 5% and 10% honey bee; the mean number of oocytes in metaphase II stage was higher than that in G1 and G4 groups. Glutathione concentration was highest in G2 (10.93 +/- 0.57). In general, gene expression levels were similar in G2 and G3, which were greater that in G1 and G4. In conclusion, the optimal concentration of black seeds honey bee that can be added to the maturation medium is 5% to obtain the highest mean MII and glutathione concentration values, and to improve gene expression in in vitro matured sheep oocytes.