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Haploidy in early bovine embryos produced in vitro

100%
Early bovine embryos (two - to sixteen blastomeres) produced in vitro were cytogenetically analysed to determine the incidence of haploidy. Follicular oocytes were matured in vitro and inseminated with sperm prepared using the swim up method. After 2-3 days of culture, chromosome slides were prepared according to the air-drying technique and stained with Giemsa. Altogether 202 embryos produced metaphase spreads. Of these 4.5% were pure haploid embryos and 5.5% displayed a haploid cell line within mosaic embryos (n/2n and n/3n). The occurrence of haploid embryos observed in this study was compared to results of other studies and a possible origin of haploidy was discussed.
The studies were performed on 890 oocytes collected from 67 ovaries. For cultivation in vitro 302 oocytes were qualified. Cytogenetic slides were made from 236 oocytes cultivated in vitro. Out of them only 103 oocytes (44%) proved to be suitable for cytogenetic analysis. It was found that: 28% of the oocytes were at metaphase I, 4% at anaphase I, 14% at telophase I and 54% at metaphase II of meiosis. Among secondary oocytes which were studied cytogenetically (metaphase II) 8% of the cells had diploid number of chromosomes. The studies showed that cytogenetic analysis could be useful to assess the maturation progress of oocytes in vitro and to study chromosome abnormalities.
Growth hormone (GH) acts as a stimulant in anabolic processes. Animal breeders and scientists are mostly interested in its role in milk and meat production. The function of the growth hormone in human and animal reproduction has recently become an area of great interest in modern research. As has already been shown, GH plays an important role in the process of gametogenesis in females and males, by stimulating gamete production and maturation as well as embryo development. The mechanisms of GH activity are still unknown. The insulin-like growth factor I (IGF-I) has shown to be the main GH mediator. GH therapy causes a considerable increase in sperm cell concentration, their motility and IGF-I content in blood. Moreover, tests have demonstrated an association between IGF-I concentration in seminal plasma and the rate of morphologically normal spermatozoa as well as cell concentration. GH and IGF-I action on sperm cells has been proven by discovering active receptors in porcine testis and in bovine spermatozoa cells.
The present study describes a rapid, simple method of bovine IVF embryo sexing by use of PCR technique. A pair of primers corresponding to the bovine amelogenin sequence has been used. The Rapid Cycler (Idaho Technology, USA) used in the current experiment enabled the PCR programme consisting of 55 cycles to be completed in less than 40 minutes. Therefore the total sexing procedure could be performed in less than 90 minutes. The described method succeded in case of 85% analysed embryos.
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