Meiotic competence of prepubertal goat oocytes

ArticleinTheriogenology 41(4):969-80 · February 1994with2 Reads
DOI: 10.1016/0093-691X(94)90512-H · Source: PubMed
Abstract
The object of this work was to evaluate in vitro maturation of follicular oocytes from the ovaries of prepubertal goats obtained from the slaughterhouse. To obtain the oocytes, follicles were dissected and classified according to their diameters. In the first experiment, oocytes were matured in vitro with granulosa cells. No significant differences were detected in the percentages of maturation between adult and prepubertal goat oocytes recovered from follicles of 2.5 to 6.0 mm in diameter (81.82 vs 72.47%, respectively). The percentage of maturation increased to 88.0% in prepubertal goat oocytes from 3.0 to 6.0-mm follicles. In the second experiment, the percentage of maturation of prepubertal goat oocytes was greater after 27 than after 24 h. In the third experiment, the maturational capacity of prepubertal goat oocytes according to follicular diameter was evaluated. The percentages of maturation after 27 h of culture with no granulosa cells were 24.14, 56.60 and 74.78%, respectively, for follicles 1.0 to 1.9 mm, 2.0 to 2.9 mm, and 3.0 to 6.0 mm in diameter. As the follicular diameter increased, growth of the oocyte as well as a greater number of oocytes with more cumulus cell layers were observed. A correlation between the diameter of the oocyte and its competence to complete in vitro maturation was also observed. Oocytes with more cumulus cell layers showed only a slight superiority in their capacity for maturation in large-size follicles (3.0 to 6.0 mm), but the difference was not significant. In conclusion, oocytes from prepubertal goats complete their growth and reach meiotic competence in follicles larger than 3.0 mm. With these oocytes it is possible to obtain in vitro maturation results similar to those from adult goats.
    • "In a previous study from our laboratory [15], the addition of adult ampulla oviductal epithelial cells to IVM media substantially improved ZP hardening, reduced the incidence of polyspermy, and enhanced the hatchability of in vitro?produced blastocysts. Several earlier studies have shown that oocytes recovered from prepubertal animals have reduced meiotic and developmental competence [7,18,19] , and it was confirmed in the present study. However , a large proportion of oocytes obtained from ewe lambs that had been co-cultured with adult oviductal epithelial cells resumed meiosis and produced significantly more blastocysts compared with the prepubertal oocytes matured without oviductal cell clusters. "
    [Show abstract] [Hide abstract] ABSTRACT: The acquisition of fertilization ability by oocytes is one of the prerequisites for successful in vitro embryo production (IVEP). In the present study, we examined the influence of conspecific ampulla oviductal epithelial cells incubated with cumulus-oocyte complexes (COCs) throughout the in vitro maturation (IVM) phase on the developmental competence and maturation-promoting factor (MPF) activity of sheep oocytes. There were six experimental groups in this study, namely four groups with and two groups without oviductal epithelial cells added to IVM media: adult COCs matured in vitro with the ampulla oviductal epithelial cells obtained from adult (AAE; G1) or prepubertal donors (PAE; G4), COCs obtained from prepubertal animals co-cultured with AAE (G2) or PAE (G3), and adult (C1) and prepubertal sheep COCs (C2) matured without oviductal epithelial cells. Co-incubation of oocytes retrieved from both adult and sexually immature donors with AAE (G1 and G2) resulted in significantly improved rates of metaphase-II (M-II) attainment and blastocyst formation as well as blastocyst development (total cell count) compared with their respective controls (C1 and C2). Prior to IVM, the activity of MPF was greater (P<0.05) for oocytes obtained from ewes (G1, G4 and C1) compared with those from ewe lambs (G2, G3 and C2). The greatest increment in MPF activity was recorded in G2 (MPF activity before IVM/MPF activity after IVM=3.62) followed by C2 and G3 (2.22 and 2.20, respectively), and then all remaining groups of oocytes (C1: 1.89, G1: 1.87, and G4: 1.86). In summary, co-incubation with AAE during the 24-hr IVM period had a positive impact on ovine oocyte competence and ensuing IVEP efficiency. A significant increase in MPF activity following IVM of G2 oocytes could be responsible, at least partly, for the improved rate of blastocyst formation after in vitro fertilization of prepubertal sheep oocytes.
    Full-text · Article · Jan 2017
    • "can be genetically modified in vitro and screened to identify the cells containing the gene of [5] making it difficult to release the cumulus-oocyte complexes (COCs) by traditional aspiration. "
    [Show abstract] [Hide abstract] ABSTRACT: Reduced developmental competence following IVF has been reported using oocyte derived from small follicles in several species including cattle, sheep and goats. No information is currently available about the effect of follicle size of the cytoplast donor on in vivo development following somatic cell nuclear transfer (SCNT) in goats. Oocytes collected from large (≥3mm) and small follicles (<3mm) were examined for maturation and in vivo developmental competence after SCNT. Significantly greater maturation rate was observed in oocytes derived from large follicles compared to that of small follicles (51.6% and 33.7%, P<0.05). Greater percent of large follicle oocytes exhibited a low glucose-6-phosphate dehydrogenase (G6PDH) activity at germinal vesicle stage compared to small follicle oocytes (54.9% and 38.7%, P<0.05). Relative mRNA expression analysis of 48 genes associated with embryonic and fetal development revealed that three genes (MATER, IGF2R and GRB10) had higher level of expression in metaphase II (MII) oocytes from large follicles compared to oocytes from small follicles. Nevertheless, no difference was observed in pregnancy rates (33.3% vs. 47.1%) and birth rates (22.2% vs. 16.7%) after SCNT between the large and small follicle groups). These results indicate that MII cytoplasts from small and large follicles have similar developmental competence when used in goat SCNT.
    Full-text · Article · Aug 2016
    • "The oocytes were evaluated under a phase-contrast microscope (Nikon, Tokyo, Japan). Oocytes were evaluated for normal fertilization according to Martino et al. (1994), on basis of oocyte that had set of male and female pronuclei in the ooplasm were considered to be fertilized normally, while the penetration rate was evaluated by the presence of sperm tail only in the ooplasm. "
    [Show abstract] [Hide abstract] ABSTRACT: Till now, the exact role of melatonin in male infertility hasn’t been fully discovered. Moreover, the intracellular signaling pathways activated by melatonin in buffalo spermatozoa especially on the level of cryopreservation process haven’t been reported. The current study aimed simply to clarify the precise role of this hormone during buffalo semen cryopreservation. Semen samples were obtained randomly from 6 fertile buffalo bulls (aged 3 to 5 years). Weekly, two consecutive ejaculates were collected from each bull for successive six weeks duration using an artificial vagina. The ejaculates were pooled to eliminate variability between the evaluated samples. After that, semen samples were subjected to extension with Tris-based extender supplemented with different concentrations of melatonin (0.1, 0.25, 0.5, 0.75 and 1 mM) Vs. Trisbased extender only (control). Then they were processed to cryopreservation and thawing to assess the different semen characteristics. It had been found that 0.1 mM of melatonin significantly (p<0.05) improved post thawing motility, viability index, acrosomal integrity, total antioxidant capacity, superoxide dismutase and glutathione reductase activity. On the other hand, it significantly (p<0.05) decreased the rate of lipid peroxidation, aspartate amino transferase, alanine aminotransferase, alkaline phosphatase and DNA fragmentation. All of these previously enhanced semen characteristics were reflected positively on its in vitro fertilizing capacity, as well as the percent of harvested embryos. In conclusion melatonin supplementation to the extension media of buffalo semen during processing significantly enhanced its characteristics. Moreover, the preceding results focusing more light on the potential roles of melatonin in regulating male reproduction. © 2014 The Mohamed El-Raey, M.R. Badr, Z.M. Rawash and G.M. Darwish.
    Full-text · Article · Apr 2014
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