Meiotic competence of prepubertal goat oocytes.
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.
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ABSTRACT: This study was conducted to investigate the relationships between oocyte meiotic competence, follicle size, and occyte-somatic cell associations in the marmoset monkey (Callithrix jacchus). Follicles were excised from ovaries of nonstimulated adult cyclic females (n = 6) collected on Day 7 of the follicular phase. Follicles were separated into size groups: large preantral (260-400 microns), periantral (420-640 microns), small antral (660-1000 microns), large antral (1020-2000 microns), and preovulatory (> 2000 microns). Partially naked and cumulus/granulosa-enclosed oocytes (n = 473) were released from follicles and cultured in Waymouth's medium with 10% fetal calf serum, 1 microgram/ml human (h) FSH, and 10 micrograms/ml hLH. Somatic cells remaining after 46 h were removed, and oocytes were fixed after 48 h and mounted for viewing. Chromatin staining and microtubulin fluorescence labeling were used to assess progression of meiotic maturation and spindle normality. The follicle size distribution and oocytesomatic cell associations are reported. Competencies of oocytes to achieve germinal vesicle breakdown (GVBD) and metaphase II (MII) increased significantly (p < 0.001) with follicular size but not with the association of somatic cells. Marmoset oocytes from antral follicles resumed (GVBD) and completed (MII) meiotic maturation with high frequencies (98% and 72%, respectively), with no significant differences among size groups of antral follicles. GVBD competence was virtually absent in oocytes from preantral follicles (2%) and was acquired coincidentally with antrum formation (60%), although MII competence was attained after the completion of antrum formation. Partially naked oocytes from small antral follicles matured with a high incidence of spindle and meiotic abnormalities (44%). Marmoset oocyte meiotic competencies are notably higher than in any other nonhuman primate species studied, and a possible explanation for this phenomenon in relation to the stage of antrum formation is offered.Biology of Reproduction 06/1995; 52(6):1234-43. · 4.03 Impact Factor
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ABSTRACT: To assess the impact of the mean oocyte diameter (MOD) on occurrence of fertilization and embryo quality in assisted reproduction cycles. Prospective observational study. Sector of Human Reproduction of the University Hospital, Faculty of Medicine of Ribeirão Preto, University of São Paulo (HCFMRP-USP). Thirty-five women undergoing intracytoplasmic sperm injection (ICSI) at the University Hospital of Ribeirão Preto from May to October 2007. MOD assessment. Occurrence of fertilization and qualitative embryo classification on 2nd and 3rd day after ICSI. We divided 160 metaphase II oocytes according to MOD into groups A (MOD below the 25th percentile), B (MOD between 25th and 75th percentile), and C (MOD above the 75th percentile). There was no statistically significant association between MOD and the occurrence of fertilization or the qualitative embryo classification on days 2 and 3. There was no statistically significant difference between groups regarding number of cells or the qualitative embryo classification on days 2 and 3. The MOD of mature oocytes does not seem to be related to the occurrence of fertilization or to the developmental quality of human embryos on days 2 and 3 after ICSI.Fertility and sterility 06/2009; 93(2):621-5. · 3.97 Impact Factor
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ABSTRACT: The present study was aimed at assessing efficacy of 3 harvesting methods on the quantity and quality of oocytes recovered for assisted reproduction procedures in goat. The average total number of oocytes recovered per ovary was significantly higher by slicing (6.54±0.39) and puncture (6.59±0.39) than by the aspiration method (4.09±0.19). However, the percentage of good quality oocytes was higher in the puncture method (71.56%), compared to the aspiration (71.27%) or slicing (61.61%) methods. The oocyte recovery was significantly lower in CL containing ovaries than that of ovaries without CL in aspiration (2.92 vs 4.57), puncture (5.89 vs 6.78) and slicing (5.40 vs 7.02) methods. However, the presence of CL did not affect the oocytes ability to reach the MII stage (75.31% vs 76.67%). The side (right or left) of the ovary not showed any significant effect on mean of total oocyte recovery and other grades of oocytes. However the large sized ovaries were yielded significantly higher number of oocytes than smaller ovaries. The results showed that the rates of COCs that reached the metaphase-II (M-II) stage were 79.88, 78.09 and 72.63% in aspiration, puncture and slicing techniques, respectively. The maturation rate was significantly lower in slicing method. The oocytes obtained were matured and parthenogenetically activated in vitro using ionomycin and 6-DMAP. There was no significant difference in the subsequent percentage of cleavage and development to blastocyst stage in vitro between the three methods of oocyte harvesting. It was concluded that though oocyte recovery, and in vitro developmental rates did not vary significantly between puncture and slicing methods, yet puncture method was found to be superior due to low debris content and recovery of more number of culture grade oocytes. Oocyte recovery by aspiration from small sized ovaries was difficult due to less number of visible follicles. Puncture method can be used as an alternative to slicing and aspiration for oocyte recovery in goat.The Indian journal of animal sciences 10/2013; 83(10):1042. · 0.13 Impact Factor