Production of sexed bovine embryos in vitro can be improved by selection of sperm treatment and co-culture system.

The study investigated the effects of sperm sorting, capacitation treatment and co-cultivation on sexed bovine in vitro embryo production. The effect of treatment and co-culture on production of embryos of the preferred sex from unsorted sperm was also studied. Sperm from five breeding bulls was used for fertilization of mature oocytes as follows: Experiment 1, sorted and unsorted sperm (bulls A-E) treated only with heparin in standard co-cultures; Experiment 2, sorted sperm (bulls A-E) treated with heparin-PHE (penicillamine, hypotaurine, and epinephrine) or heparin-caffeine in drop co-cultures; and Experiment 3, unsorted sperm (bull E) treated with either heparin-PHE or heparin-caffeine in both standard and drop co-cultures.

Cortical Granule Distribution and Expression Pattern of Genes Regulating Cellular Component Size, Morphogenesis, and Potential to Differentiation are Related to Oocyte Developmental Competence and Maturational Capacity In Vivo and In Vitro.

Polyspermia is an adverse phenomenon during mammalian fertilization when more than one sperm fuses with a single oocyte. The egg cell is prepared to prevent polyspermia by, among other ways, producing cortical granules (CGs), which are specialized intracellular structures containing enzymes that aim to harden the zona pellucida and block the fusion of subsequent sperm. This work focused on exploring the expression profile of genes that may be associated with cortical reactions, and evaluated the distribution of CGs in immature oocytes and the peripheral density of CGs in mature oocytes.

Genes regulating hormone stimulus and response to protein signaling revealed differential expression pattern during porcine oocyte in vitro maturation, confirmed by lipid concentration.

Genes influencing oocyte maturation may be valuable for predicting their developmental potential, as well as discerning the mechanistic pathways regulating oocyte development. In the presented research microarray gene expression analysis of immature and in vitro matured porcine oocytes was performed. Two groups of oocytes were compared in the study: before (3 × n = 50) and after in vitro maturation (3 × n = 50).

Expression of selected mitochondrial genes during in vitro maturation of bovine oocytes related to their meiotic competence.

The main goal of this study was to characterize the expression patterns of genes which play a role in mitochondrial DNA biogenesis and metabolism during the maturation of bovine oocytes with different meiotic competence and health. Meiotically more and less competent oocytes were obtained separately either from medium (MF) or small (SF) follicles and categorized according to oocyte morphology into healthy and light-atretic. The four oocyte categories were matured and collected after 0, 3, 7, 16 and 24 h of maturation.

Transcriptomic Pattern of Genes Regulating Protein Response and Status of Mitochondrial Activity Are Related to Oocyte Maturational Competence-A Transcriptomic Study.

This paper aims to identify and describe new genetic markers involved in the processes of protein expression and modification reflected in the change of mitochondrial activity before and after in vitro maturation of the oocyte. Porcine oocytes collected from the ovaries of slaughtered landrace gilts were subjected to the process of in vitro maturation. Transcriptomic changes in the expression profile of oocyte genes involved in response to hypoxia, the transmembrane protein receptor serine threonine kinase signaling pathway, the "transforming growth factor β receptor signaling pathway", "response to protein stimulus", and "response to organic substance" were investigated using microarrays.

Supplementation of l-carnitine during in vitro maturation improves embryo development from less competent bovine oocytes.

The present study was designed to define the impact of l-carnitine, supplemented during maturation, on bovine oocytes with different meiotic competence in terms of their IVF outcomes. Meiotically more competent (MMC) and less competent (MLC) oocytes were obtained separately from differently sized follicles at selected phases of folliculogenesis. The oocytes were matured with or without l-carnitine, fertilized and cultured to the blastocyst stage.

Aneuploidy Detection and mtDNA Quantification in Bovine Embryos with Different Cleavage Onset Using a Next-Generation Sequencing-Based Protocol.

Bovine embryos are now routinely used in agricultural systems as a means of disseminating superior genetics worldwide, ultimately with the aim of feeding an ever-growing population. Further investigations, common for human IVF embryos, thus have priority to improve cattle IVF, as has screening for aneuploidy (abnormal chromosome number). Although the incidence and consequences of aneuploidy are well documented in human preimplantation embryos, they are less well known for the embryos of other animals.

Energy Status Characteristics of Porcine Oocytes During In Vitro Maturation is Influenced by Their Meiotic Competence.

The characteristics of energy status in porcine oocytes as related to their meiotic competence and in vitro maturation were studied. Cycling pubertal gilts in the early luteal to early follicular phases of the ovarian cycle were used as oocyte donors. The oocytes recovered from medium (MF) or small follicles (SF) were considered meiotically more or less competent, respectively.

Mitochondrial patterns in bovine oocytes with different meiotic competence related to their in vitro maturation.

This study was designed to specify chromatin and mitochondrial patterns in bovine oocytes with different meiotic competence in relation to maturation progress, resumption of meiosis, MII onset and completion of maturation. Oocytes with greater or lesser meiotic competence, recovered separately from medium (MF) and small follicles (SF), were categorized according to morphology. Four oocyte categories, healthy and light-atretic MF and healthy and light-atretic SF oocytes were matured and collected at 0, 3, 7, 16 and 24 h of maturation.

Association of the transcription profile of bovine oocytes and embryos with developmental potential.

Although improvements in culture system have enhanced in vitro embryo production, success rates are still not adequate. The reasons for developmental arrest of a part of in vitro produced embryos are unknown, but are connected in part with low cytoplasmic competence of oocytes. The immaturity of cytoplasm can negatively influence fertilization efficiency and subsequent progression through embryonic genome activation (EGA), which are necessary steps in further pre-implantation development.

Characteristics of bovine oocytes with different meiotic competence in terms of their mitochondrial status and expression of nuclear-encoded factors.

The present study was designed to characterize bovine oocytes with different meiotic competence and atresia levels in terms of their mitochondrial status. Oocyte subpopulations were recovered either from medium (MF) or small (SF) follicles and categorized as healthy, light-atretic and mid-atretic according to oocyte morphology. Mitochondrial activity, morphology and distribution, adenosine triphosphate (ATP) content and expression of mitochondrial transcription factor A (TFAM) and nuclear respiratory factor 1 (NRF1) were assessed before (GV) and after (MII) maturation.

Efficiency of in vitro fertilization is influenced by the meiotic competence of porcine oocytes and time of their maturation.

The effect of meiotic competence of oocytes and time of their maturation on the efficiency of fertilization was studied in pigs. Cycling gilts with synchronized estrous cycles were used as oocyte donors. To obtain oocytes with different meiotic competence, oocytes were recovered separately from small and medium follicles in the early, middle and late luteal or early follicular phase.

Early oocyte penetration can predict the efficiency of bovine embryo production in vitro.

The aim of this work was to characterize oocyte fertilization and embryo cleavage in nine AI bulls to find parameters suitable for prediction of in vitro fertility. According to the d8 blastocysts rate, they were categorized as high, medium and low productive (HP, MP and LP, mean: 25.4, 21.

Evaluation of chromatin integrity of motile bovine spermatozoa capacitated in vitro.

The efficiency of in vitro embryo production is highly variable amongst individual sires in cattle. To eliminate that this variability is not caused by sperm chromatin damage caused by separation or capacitacion, chromatin integrity was evaluated. Seventeen of AI bulls with good NRRs but variable embryo production efficiency were used.

Efficiency and kinetics of the in vitro fertilization process in bovine oocytes with different meiotic competence.

The aim of the study was to investigate the efficiency and kinetics of fertilization in oocytes with different meiotic competence, as defined by the phase of the follicular wave and follicle size. Oocytes were recovered from cows with synchronized estrus cycles, slaughtered in either the growth (day 3) or the dominant (day 7) phase, separately from large, medium and small follicles. The oocytes were matured and fertilized by a standard protocol.

A potential relationship between the acrosome response characteristics of bovine spermatozoa and their in vitro fertilizing ability.

The aim of the work was to study a potential relationship between acrosome response characteristics of bovine spermatozoa and their ability to fertilize oocytes and produce in vitro embryos. Sperm of artificial insemination bulls with a high rate (22.0 +/- 4.

Gene expression in bovine embryos derived from oocytes with different developmental competence collected at the defined follicular developmental stage.

The aim of this study was to compare the expression of selected genes in bovine embryos developed from oocytes with different developmental competence. Four oocyte populations were collected, separately either from small (2-5 mm) or medium (6-10 mm) follicles, in the growth/stagnation (G/S) or dominance/regression (D/R) stage of the first follicular wave. They were matured, fertilized and cultured to D7 or D8 blastocysts by a standard protocol.

Embryos produced in vitro from bulls carrying 16;20 and 1;29 Robertsonian translocations: efficiency and kinetics of oocyte fertilization and embryo development.

The present experiments were designed to study the effects of Robertsonian translocations on the efficiency and kinetics of in vitro fertilization and early and advanced embryo development. Spermatozoa from bulls with rob(16;20), rob(1;29) and normal karyotype (A, B and C, respectively) were used. Oocytes were matured, fertilized and cultured by the standard protocol described previously.

Embryos produced in vitro from bulls carrying 16;20 and 1;29 Robertsonian translocations: detection of translocations in embryos by fluorescence in situ hybridization.

Robertsonian translocation rob(16;20) in the heterozygous state was discovered in a subfertile bull of the Czech Siemmental breed. A chromosomal analysis of its family has shown that this dicentric fusion is formed de novo. The present experiments were designed to detect rob(16;20) and determine its incidence for in vitro produced embryos, using fluorescence in situ hybridization (FISH) and rob(1;29) as a detection control.

QF-PCR examination of parental and meiotic origin of trisomy 21 in Central and Eastern Europe.

Study of parental/meiotic origin of free trisomy 21 in nuclear families from Russia (70 cases), Ukraine (32 cases), and 22 from Germany revealed maternal nondisjunction in 77.3% (Germany), 93.8% (Ukraine), and 91.

[Chromosome Y microdeletions in Czech men with severe reproductive disorders].

Background: The Y chromosome microdeletions belong to the frequent genetical causes of male infertility. The aim of our study was to introduce reliable molecular genetic diagnosis of Y chromosomal microdeletions and to determine the prevalence of Y chromosomal microdeletions in Czech males with serious reproductive disorders.

Methods And Results: The Y chromosome microdeletions were screened in 198 Czech men with serious reproductive disorders with decreased sperm count.

Developmental competence of bovine oocytes: effects of follicle size and the phase of follicular wave on in vitro embryo production.

Developmental competence of bovine oocytes collected from follicles of different size categories (in either the growth or the dominant phase of the first follicular wave) was studied, with the aim of improving in vitro embryo production. Estrus and ovulation of 39 cyclic Holstein dairy cows were synchronized by two prostaglandin F2alpha treatments at 11-day intervals and one hCG treatment on the day of onset of estrus (Day 0). Cows with follicles in either the growth (Day 3, n=25) or the dominant phase (Day 7, n=14) were slaughtered, and follicles >5 mm were counted.

[Medical genetics in reproductive medicine].

Reproductive genetics (RG) is another new field of medical genetics, integrated with reproductive medicine, assisted reproduction and developmental genetic. RG is closely linked to the perioconceptional prevention, perinatology, ultrasound and biochemical screening in the end of the first and beginning of the second trimesters. RG is based on the system of specialized genetic counseling, clinical cytogenetics, molecular cytogenetics and molecular genetics to provide prefertilization, preimplantation and classical prenatal diagnosis in the Ist to IIIrd trimesters.

Frequency of aneuploidy in pig oocytes matured in vitro and of the corresponding first polar bodies detected by fluorescent in situ hybridization.

The objectives of this study were to develop a two-color fluorescent in situ hybridization (FISH) method for evaluating aneuploidy in gilt oocytes using chromosome-specific DNA probes, and to establish baseline frequencies of aneuploidy in pig oocytes matured in vitro. The ovaries were collected from gilts at the local slaughterhouse. Immature oocytes were isolated by slicing the cortex of the ovaries.