Low oxygen environment and astaxanthin supplementation promote the developmental competence of bovine oocytes derived from early antral follicles during 8 days of in vitro growth in a gas-permeable culture device

Pre-maturational culture promotes the developmental competence of bovine oocytes derived from an 8-day <i>in vitro</i> growth culture system

“…IVG culture of OCGCs was performed using an 8-day IVG culture system with a 96-well gas-permeable culture device (Lumox, Numbrecht, Germany) under 5% O 2 for four days. This was followed by an increase to 20% O2 during the last four days of culture, as previously reported [1].…”

“…Moreover, the blastocyst rate could not exceed 20% when oocytes were grown for more than 8 d in gas-impermeable culture devices under the constant 5% or 20% and in a 5-20% O2 environment without pre-IVM [18]. However, the blastocyst rates of oocytes grown using the present IVG culture system were lower than those derived from d8 GP + Ax IVG culture without pre-IVM in a constant 5% O2 environment (28%) [1]. Furthermore, the developmental competence of oocytes in the present study was still lower than that in vivo-derived oocytes (approximately 30-60% blastocyst rate [4]; Supplementary Table 1).…”

“…In vitro growth (IVG) culture systems provide an environment for immature and developmentally incompetent oocytes to grow and acquire maturational and developmental competence in vitro. We recently described an 8-day IVG culture system that yielded developmentally competent oocytes after culture in a gas-permeable culture (GP) device with astaxanthin (Ax) as an antioxidant [1]. The oxygen environment was switched from low (5%) to high (20%) on Day 4 of culture (8d GP + Ax 5-20% O2 IVG culture system).…”

“…In contrast, Abdel-Ghani et al [14] determined that in vivo-grown oocytes between 110 and ≤ 115 µm in diameter had higher developmental competence after 5 h of pre-IVM supplemented with IBMX and low-concentration FSH than the control group. Oocytes grow to approximately 113-114 µm when cultured using the 8d GP + Ax 5-20% O 2 IVG culture system [1]. Therefore, the present study examined whether the developmental competence of bovine oocytes would be improved if 5 h pre-IVM culture [14] is incorporated after IVG culture.…”

Changes in Nucleus and Cytoplast During Oocyte Maturation: Involvement in Embryo Production

“…Enrichment of maturation media with cumulus cells (Al Zeidi et al, 2022), growth factors and hormones (Bunel et al, 2020;Ko et al, 2021;Kumar et al, 2020;Wolff et al, 2022), and other factors (Martínez-Quezada et al, 2021;Zabihi et al, 2021;Saini et al, 2022;Chelenga et al, 2022) improves oocyte maturation and embryo development thereafter (Gordon 2003;Baruffi et al, 2004;Somfai et al, 2012). In addition, super-stimulation of ovarian follicles via gonadotropin injections resulted in changes in small, medium, and large follicles according to the number and dose of gonadotropin injections and side of the ovary (Abdelnaby et al, 2021).…”