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Prepubertal goat in vitro matured/in vitro fertilised oocytes produce only a small percentage of blastocysts. The present study examines the incidence of chromosomal anomalies in 2- to 4-cell embryos in vitro produced (IVP) from prepubertal oocytes fertilised with the semen of two males. Cumulus-oocyte complexes were obtained by slicing ovaries from slaughtered prepubertal goats. Oocytes were matured in TCM199 supplemented with 20% heat inactivated Donor Bovine Serum (DBS), 10 μg/ml FSH + 10 μg/ml LH + 1 μg/ml 17β-oestradiol for 27 h at 38.5 °C in 5% CO2 in air. IVM oocytes were inseminated with the sperm from two males prepared using the swim-up and heparin-capacitation procedures. At 24 h post-insemination (hpi) the oocytes were transferred to 100 μl drops of SOF medium for a further 24 h. At 17 hpi a sample of oocytes was stained with lacmoid to evaluate the nuclear stage after fertilisation. The cleavage rate was determined at 24, 36 and 48 hpi and chromosome slides were prepared according to the gradual-fixation technique and stained with Leishman. A total of 1070 2- to 4-cell embryos from prepubertal goat oocytes were studied, but it was only possible to analyse 241 cytogenetically. Of these, 40% exhibited a normal diploid chromosome complement, 59% were haploid and 1% were triploid. There were significant differences between the two males in sperm oocyte penetration and oocyte cleavage but no differences were found in chromosomal anomalies. In conclusion, the low number of embryos karyotyped and the high number of haploid embryos found in this study suggested a high incidence of abnormal fertilised embryos and deficient cytoplasmic maturation of the oocyte which inhibits sperm head decondensation.

ContentsThe zona pellucida "ZP# surface features of ovulated\ inmature and in!vitro!matured goat oocytes were evaluated by scanning electron microscopy[ The in vitro maturation "IVM# process of the ZP surface of oocytes from prepubertal and adult goats were also compared[ Ovulated oocytes were collected from superovulated adult goats[ Immature oocytes were recovered from slaughterhouse ovaries of prepubertal and adult goats[ In! vitro!matured oocytes from adult and prepubertal goats were obtained after culture in TCM088 supplemented with 19) oes! trous goat serum ¦ 09 mg:ml FSH ¦ 09 mg:ml LH ¦ 0 mg:ml estradiol 06b for 16 h at 27[4>C in 4) CO 1 in air[ All oocytes were _xed in 1[4) glutaraldehyde and post_xed in 0) osmium tetroxide[ Before IVM\ the ZP surface of immature oocytes showed a rough surface with tight holes "Type I ZP#[ After the maturation process\ the ZP surface acquired a lattice!like appearance with the outermost layer characterized by the pres! ence of shallower large holes "Type II ZP#[ A higher percentage of oocytes showing the mature type II ZP surface was observed in ovulated than in in!vitro!matured oocytes "71[5 versus 45[6)\ respectively\ p ³ 9[94#[ No signi_cant di}erences were observed in ZP surface features when the IVM process of oocytes "imma! ture and in!vitro!matured oocytes# from adult and prepubertal females was compared[ These results show that the morphology of the ZP surface is related to the oocyte maturity in caprine[ The IVM process gives rise to an adequate and similar devel! opment of the ZP surface in oocytes from adult and prepubertal goats[ U[ S[ Copyright Clearance Center Code Statement] 9825Ð5657:88:2394Ð9306,03[99:9 Lo à cher gekennzeichnet war "Typ 1 ZP#[ Bei ovulierten Eizellen wurde ein signi_kant ho à herer Anteil des Types 1 der ZP beo! bachtet "71\5) gegenu à ber 45\6)^p ³ 9\94#[ Beim Vergleich der ZP!Struktur unreifer und in vitro gereifter Eizellen wurden weder bei Eizellen von pra Ãpuberalen noch von erwachsenen Ziegen Unterschiede gefunden[ Die Ergebnisse zeigen\ da) die Morphologie der Zona pellucida Ober~a Ãche von der Reifung der Eizellen abha Ãngt[ Die In vitro Reifung fu à hrte zu einem ausreichend vergleichbaren Entwicklungsgrad der ZP!Ober! a Ãche\ sowohl bei pra Ãpuberalen als auch bei erwachsenen Ziegen[

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