Altered chromatin condensation of heat-stressed spermatozoa perturbs the dynamics of DNA methylation reprogramming in the paternal genome after in vitro fertilisation in cattle.

Shortly after penetration of the oocyte, sperm DNA is actively demethylated, which is required for totipotent zygotic development. Aberrant DNA methylation is thought to be associated with altered chromatin condensation of spermatozoa. The objectives of this study were to investigate the dynamics of DNA methylation reprogramming in the paternal pronucleus and subsequent fertilisation potential of heat-stressed bull spermatozoa having altered chromatin condensation.

Bovine spermatozoa react to in vitro heat stress by activating the mitogen-activated protein kinase 14 signalling pathway.

Heat stress has long been recognised as a cause of subfertility in farm animals. The objectives of the present study were to elucidate the effect of heat stress on sperm function and involvement of the mitogen-activated protein kinase (MAPK) 14 signalling pathway. Spermatozoa incubated for 4 h at a physiological temperature (38.

Boar seminal plasma components and their relation with semen quality.

Select boar seminal plasma (SP) components and their relation to semen quality were investigated. Thirty nine boars from three artificial insemination (AI) centers were divided into group A (GA: > 80% normal sperm and >70% motility) and group B (GB: < 80% normal sperm and < 70% motility). Each ejaculate was collected and semen volume, concentration, sperm motility (computer aided semen analysis; CASA), morphology, and vitality (both eosin nigrosin staining) were investigated.

Oocyte quality determines bovine embryo development after fertilisation with hydrogen peroxide-stressed spermatozoa.

Exposure of gametes to specific stressors at sublethal levels can enhance the gametes' subsequent performance in processes such as cryopreservation. In the present study, bull spermatozoa were subjected to H₂O₂ for 4 h at 100-, 200- and 500-μM levels; computer-assisted sperm analysis (CASA) and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay were used for evaluation of subsequent sperm motility and DNA integrity, respectively. Exposure of spermatozoa to H₂O₂ did not affect sperm motility but DNA integrity was negatively affected by 500 μM H₂O₂ compared with mock-exposed spermatozoa, whereas both motility and DNA integrity were affected compared with untreated spermatozoa.

Scrotal insulation and its relationship to abnormal morphology, chromatin protamination and nuclear shape of spermatozoa in Holstein-Friesian and Belgian Blue bulls.

The objectives of this study were to identify the stages of spermatogenesis susceptible to elevated testicular temperature in terms of sperm motility, viability, morphology, chromatin protamination and nuclear shape. The latter two valuable parameters are not included in routine semen analysis. Scrotal insulation (SI) was applied for 48 h in 2 Holstein-Friesian (HF) and 2 Belgian Blue (BB) bulls and semen was collected at 7 d intervals along with semen collection of a non-insulated bull of each breed.

Effectiveness of the sperm quality analyzer (SQA-Vp) for porcine semen analysis.

The Sperm Quality Analyzer (SQA-Vp) was evaluated for assessing concentration and motility of porcine semen. Both fresh and diluted semen from 50 different boars from a commercial artificial insemination (AI) centre were investigated. For the fresh ejaculate, the concentration obtained with SQA-Vp was compared with a photometer and a haemocytometer.

Influence of different centrifugation protocols on equine semen preservation.

Three experiments were conducted to evaluate the impact of centrifugation on cooled and frozen preservation of equine semen. A standard centrifugation protocol (600 x g for 10 min=CP1) was compared to four protocols with increasing g-force and decreased time period (600 x g, 1200 x g, 1800 x g and 2400 x g for 5 min for CP2, 3, 4, and 5, respectively) and to an uncentrifuged negative control. In experiment 1, the influence of the different CPs on sperm loss was evaluated by calculating the total number of sperm cells in 90% of the supernatant.

Expression and putative function of fibronectin and its receptor (integrin alpha(5)beta(1)) in male and female gametes during bovine fertilization in vitro.

Fibronectin (Fn) is a 440 kDa glycoprotein assumed to participate in sperm-egg interaction in human. Recently, it has been demonstrated that Fn--when present during bovine IVF--strongly inhibits sperm penetration. The present study was conducted firstly to evaluate the expression of Fn and its integrin receptor (alpha(5)beta(1)) on male and female bovine gametes using indirect immunofluorescence and secondly, to determine the function of Fn during bovine IVF.

Dynamics of boar semen motility inhibition as a semi-quantitative measurement of Bacillus cereus emetic toxin (Cereulide).

Qualitative and quantitative application of a computer assisted sperm analyzer (CASA) for detection and quantification of cereulide was described. The plot of the decrease of the percentage of boar semen progressive motility (PMOT%) in function of time and the visual inspection of curves provided a qualitative comparison between different samples (curve slope corresponds to the amount of cereulide in the sample). If the change of PMOT% over a time required for achieving PMOT% drop to 10% (DeltaPMOT%/Deltatau) is plotted against the standard curve (obtained with known concentrations of valinomycin), a semi-quantitative estimation of the amount of cereulide in the sample is obtained.

Automated sperm morphometry and morphology analysis of canine semen by the Hamilton-Thorne analyser.

Computer-assisted sperm morphometry has the potential to eliminate several drawbacks inherent to the current methods of sperm morphology evaluation, and allows for the identification of subtle sperm characteristics which cannot be detected by visual evaluation. In the present study, the Metrix Oval Head Morphology software implemented in the Hamilton-Thorne CEROS (version 12.1; HTR 12.

Effect of blood admixture on in vitro survival of chilled and frozen-thawed canine spermatozoa.

Hematospermia in the dog usually occurs secondary to benign prostatic hypertrophy or trauma of the penis or prepuce during semen collection. Regarding the difficulty of removing blood cells from a hematospermic sample, the present study was performed to determine whether blood contaminated ejaculates can still be chilled (4 degrees C) or frozen (-196 degrees C) without an additional decrease in sperm quality. In the first experiment, blood additions of up to 10% exerted no negative effects on the functional characteristics of canine spermatozoa cooled (4 degrees C) and stored for 4 days in an egg-yolk-Tris extender.

Effect of whole blood and serum on bovine sperm quality and in vitro fertilization capacity.

Under physiologic conditions, low concentrations of blood may be present in the uterine fluid of the estrous cow at the moment of insemination. To decrease the insemination dose and to obtain good insemination results with less fertile semen, more invasive insemination methods such as utero tubal junction (UTJ) insemination can be used. More invasive insemination methods increase the risk of damaging the hyperemic endometrium, with blood in the uterine fluid as result.

Effect of technical settings on canine semen motility parameters measured by the Hamilton-Thorne analyzer.

Computerized measuring devices are needed to assess canine semen quality objectively both for research and practical purposes. As internal image settings may influence the results considerably, the effect of different technical settings and semen processing on the parameters assessed by the Hamilton-Thorne Ceros 12.1 semen analyzer (HTR Ceros 12.

Use of the Sperm Quality Analyzer (SQA II-C) for the assessment of dog sperm quality.

In the present study, an automated system for sperm analysis, the Sperm Quality Analyzer (SQA II-C), was tested as a potential tool for the assessment of dog sperm quality. In the first experiment the device displayed a good repeatability of measurements for semen of medium and high quality, as evidenced by a low coefficient of variance (CV; 0.08), whereas a high CV (0.