Ovarian characteristics and in vitro nuclear and cytoplasmic oocyte maturation in Duroc and Landrace pigs

Abstract

Differences in total number of piglets born per litter are observed between the Norwegian Duroc (ND) sire and Norwegian Landrace (NL) dam line. The aim of this study was to evaluate ovarian characteristics, and in vitro nuclear and cytoplasmic oocyte maturation in both breeds. One day after weaning, follicular phase ovaries were collected. Ovary length and weight were measured and the number of follicles (< 3 mm and 3–8 mm) was counted. Cumulus‐oocyte complexes (COCs) were collected and matured for 48 hr. To assess cumulus expansion, COC area was analysed at 0 and 20 hr. Nuclear maturation and cortical granule (CG) distribution were analysed at 20 and 48 hr, and total glutathione (GSH) was measured at 48 hr to further elucidate cytoplasmic maturation. In first parity sows, a smaller ovary length and fewer 3 to 8 mm follicles were observed in ND compared to NL. For all sows, ND COCs covered a significantly smaller area at 0 hr, but a higher cumulus expansion ratio was observed at 20 hr compared to NL (364 ± 46% versus. 278 ± 27%, p < 0.001). At 20 hr, more ND oocytes exhibited advanced stages of nuclear maturation, while more NL oocytes showed advanced stages of CG distribution. Nuclear maturation to MII stage at 48 hr did not differ between ND and NL oocytes (90.1% and 87.7%, respectively). Moreover, no significant differences were observed for GSH content or CG distribution after maturation. In conclusion, differences with regard to ovarian characteristics as well as to cumulus expansion, and nuclear and cytoplasmic oocyte maturation at 20 hr were observed between the breeds. Further studies are required to determine if this subsequently affects in vitro fertilization and embryo development.

Effects of Diluent pH on Enrichment and Performance of Dairy Goat X/Y Sperm

“…Mammalian in vitro fertilization has become an important and routine biotechnology for animal reproduction (Jochems et al, 2021;Redel et al, 2021;Seekford et al, 2021), which requires high-quality oocytes, and is closely related to sperm quality (Rowlison et al, 2021;Shah and Andrabi, 2021). The pH environment to which semen is exposed can affect the motility and metabolic level of spermatozoa, with metabolism and motility being hindered and motility being diminished in a weakly acidic environment.…”

The Clinical Application of Growth Hormone and Its Biological and Molecular Mechanisms in Assisted Reproduction

“…While acquiring developmental competence, oocyte cytoplasm matures with an accumulation of mRNA, proteins, substrates, and nutrients, which ultimately fosters embryonic developmental competence. The distribution of cortical granules in the cortical cytoplasm is specific to immature oocytes while the distribution of cortical granules just beneath the plasma membrane is specific to mature oocytes [121,122], and thus the cortical granule distribution has been used as a reliable indicator for the cytoplasmic maturation of oocytes. The addition of GH/IGF1 to an in vitro maturation (IVM) medium has influenced the in vitro cytoplasmic maturation of equine oocytes, which was required to achieve complete maturation competence [123,124].…”

Pterostilbene Alleviates Chlorpyrifos-Induced Damage During Porcine Oocyte Maturation

“…Oocyte maturation, referring to nuclear and cytoplasmic maturation, is an essential event in mammalian reproduction, and determines the progress of reproductive technologies such as in vitro fertilization (IVF), somatic cell nuclear transfer (SCNT) and intracytoplasmic sperm injection (ICSI) (Huan et al, 2015b). During nuclear maturation, the precise regulation of spindle assembly and chromosome alignment is required to ensure the normal meiosis, and cytoplasmic maturation is the spatial distribution of organelles, and also includes the function of the redox system (Lee et al, 2016;Jochems et al, 2021). When oocytes are exposed to environmental pollutants, spindle assembly and chromosome alignment are disturbed, and the balance of redox system is destroyed (Chen et al, 2020;Shi et al, 2021).…”