The incidence of polyploidy and mixoploidy in early bovine embryos derived from in vitro fertilization

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Metabolic and endocrine profiles and reproductive parameters in dairy cows under grazing conditions: effect of polymorphisms in somatotropic axis genes

<p>Abstract</p> <p>Background</p> <p>The present study hypothesized that GH-AluI and IGF-I-SnabI polymorphisms do change the metabolic/endocrine profiles in Holstein cows during the transition period, which in turn are associated with productive and reproductive parameters.</p> <p>Methods</p> <p>Holstein cows (Farm 1, primiparous cows, n = 110, and Farm 2, multiparous cows, n = 76) under grazing conditions were selected and GH and IGF-I genotypes were determined. Blood samples for metabolic/endocrine determinations were taken during the transition period and early lactation in both farms. Data was analyzed by farm using a repeated measures analyses including GH and IGF-I genotypes, days and interactions as fixed effects, sire and cow as random effects and calving date as covariate.</p> <p>Results and Discussion</p> <p>Frequencies of GH and IGF-I alleles were L:0.84, V:0.16 and A:0.60, B:0.40, respectively. The GH genotype was not associated with productive or reproductive variables, but interaction with days affected FCM yield in multiparous (farm 2) cows (LL yielded more than LV cows) in early lactation. The GH genotype affected NEFA and IGF-I concentrations in farm 1 (LV had higher NEFA and lower IGF-I than LL cows) suggesting a better energy status of LL cows.</p> <p>There was no effect of IGF-I genotype on productive variables, but a trend was found for FCM in farm 2 (AB cows yielded more than AA cows). IGF-I genotype affected calving first service interval in farm 1, and the interaction with days tended to affect FCM yield (AB cows had a shorter interval and yielded more FCM than BB cows). IGF-I genotype affected BHB, NEFA, and insulin concentrations in farm 1: primiparous BB cows had lower NEFA and BHB and higher insulin concentrations. In farm 2, there was no effect of IGF-I genotype, but there was an interaction with days on IGF-I concentration, suggesting a greater uncoupling somatropic axis in AB and BB than AA cows, being in accordance with greater FCM yield in AB cows.</p> <p>Conclusion</p> <p>The GH and IGF-I genotypes had no substantial effect on productive parameters, although IGF-I genotype affected calving-first service interval in primiparous cows. Besides, these genotypes may modify the endocrine/metabolic profiles of the transition dairy cow under grazing conditions.</p

Aneuploidy Detection in Pigs Using Comparative Genomic Hybridization: From the Oocytes to Blastocysts

Data on the frequency of aneuploidy in farm animals are lacking and there is the need for a reliable technique which is capable of detecting all chromosomes simultaneously in a single cell. With the employment of comparative genomic hybridization coupled with the whole genome amplification technique, this study brings new information regarding the aneuploidy of individual chromosomes in pigs. Focus is directed on in vivo porcine blastocysts and late morulas, 4.7% of which were found to carry chromosomal abnormality. Further, ploidy abnormalities were examined using FISH in a sample of porcine embryos. True polyploidy was relatively rare (1.6%), whilst mixoploidy was presented in 46.8% of embryos, however it was restricted to only a small number of cells per embryo. The combined data indicates that aneuploidy is not a prevalent cause of embryo mortality in pigs

Haploidy in early bovine embryos produced in vitro

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

Morphology and developmental potential of bovine parthenotes after spontaneous activation in vitro

Spontaneous parthenogenetic activation of bovine oocytes in an in vitro maturation and fertilization system (IVM/IVF) is described. Altogether, 1403 follicular oocytes, collected by the aspiration method, were matured in vitro and then cultured without insemination in the same conditions as a group of inseminated oocytes. After 48-72 h of additional culture, 141 oocytes (10%) were found to be spontaneously activated. Morphological evaluation revealed that the number of blastomeres within parthenotes ranged from 2 to 16 cells, with a minority (15.7%) comprising of 9-16 blastomeres. According to a cytogenetic analysis, only 1.2% of the analysed parthenotes consisted of more than 9 cells. Parthenotes may not be distinguished from embryos produced in vitro and spontaneous parthenogenetic activation in an IVM/IVF system indicates suboptimal culture conditions. A group of non-inseminated oocytes should be included in each experiment to serve as a control. Spontaneously activated bovine parthenotes only occasionaly developed beyond the 8-blastomere stage in a common IVM/IVF system. The incidence of parthenotes interferes with the efficiency of in vitro embryo production but it is doubtful whether it lowers the pregnancy rate after transfer of IVF embryos

Identification of synaptonemal complexes in postnatal oocytes from one-day-old puppies of domestic dog [Canis familiaris]

The present paper describes a synaptonemal complexes analysis carried out on oocytes collected from the ovaries of one-day-old puppies of domestic dog (Canis familiaris). Ovaries have been collected from 20 individuals altogether. Synaptonemal complexes were identified in oocytes originating from two puppies. It is concluded that the onset of canine female meiosis may occur earlier than previously reported