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3297 Uppsatser om Sperm quality - Sida 1 av 220

Effekten av Bisfenol A (BPA) på hanråttors (Rattus norvegicus) reproduktion

Today evidence exist that environmental chemicals deteriorate male Sperm quality and that testicular cancer is increasing. Bisphenol A (BPA) is a chemical with estrogenic effects used in the manufacture of polycarbonate plastic and are found in, for instance, plastic boxes, feeding bottles and food containers. Much of the research on how men's reproductive ability is influenced are performed on rats. This review article complies how male rat reproduction is affected by BPA as a model for humans. Studies have investigated how sperm are affected, hormonal changes during reproduction and how reactive oxygen species (ROS) affects sperm.

Kromatinstabilitet som grund för kvalitetsbedömning av hingstsperma :

This study is part of a project to evaluate and develop metods to control the semen quality in stallions. The study was carried out in cooperation between SLU and Flyinge AB. The objective of the study was to analyse -if there are individual differences in sperm chromatin integrety between different stallions -if there is a correlation between subjectively evaluated sperm motility and sperm chromatin integrity -if sperm chromatin integrity is changed after selection of the semen with a centrifugation method through the silica-spheres, gradient or a single-layer, i.e to use the chromatin integrity analysis as a method to evaluate the selection method. The use of chilled transported semen has increased a lot during the last 10 years, especially among the Swedish warmblood breed. Because the foaling percentage has decreased with the increased use of chilled transported semen, there is a need to develop methods to control the Sperm quality. Evaluation of the chromatin integrity could be one way to evaluate the quality of the semen. Chromatin is the DNA in the nucleus of the sperm.

Könsselektering av spermier från lantbrukets husdjur

Millions of preselected progeny have been born since the development of The Beltsville Sperm Sexing Technology 1986. The method is based on flow cytometry and sorting is done on the basis of DNA difference of the X- and Y-chromosomes. Preselection of progeny provides an opportunity to obtain genetic gain and increased production as well as increased animal welfare and decreased environmental impact. However, the method is associated with low fertility, high costs and uncertainty whether the sorting process contributes to DNA damage and thereby results in genetically impaired progeny. Today, sex sorted sperm is only commercially available in the bovine industry, due to the fact that bull sperm is more suitable for selection than sperm from other species.

Användning av könssorterad sperma i nötkreatursaveln :

Almost for as long as there has been breeding on bovine species, there has been a wish to have a higher proportion of offspring of either one or the other gender. In dairy cattle, heifers are more valuable, while in beef stock bulls are preferred. Semen is sorted based on the difference in DNA content between the X- and Y-chromosome in the genome of the sperm. X-chromosomes contain on average between 3,70 to 4,22% more genetic material than the Y-chromosome. Commercially it is the method of flow cytometry that is being used, which is always under improvement.

Testikelmått och daglig spermieproduktion hos svenska halvblodshingstar :

Testicular measurements and daily sperm output (DSO) are important factors affecting reproductive capacity of stallions. In the present study testicular measurements of 10 Swedish half-blood stallions were determined (height, length, width and volume). Ejaculates were collected from each stallion once daily for 10 days to evaluate some important seminal characteristics: gel-free ejaculate volume, sperm concentration, percent progressively motile spermatozoa and total number of spermatozoa (TSN). The gel-free ejaculate volume was measured with a graduated cylinder, the sperm concentration was counted in a Bürker chamber, the sperm motility was estimated in a phase-contrast microscope and TSN was determined by multiplying the gel-free seminal volume by the sperm concentration. Testicular measurements were as follows (left and right testis): height 7,5 cm and 7,8 cm, length 10,6 cm and 10,8 cm, width 6,5 cm and 6,6 cm, volume 278,2 cm3 and 293,8 cm3, scrotal width 12,3 cm and total testicular volume 572,0 cm3 .

Kvalitetsbedömning av selekterad och oselekterad hingstsperma med hjälp av flödescytometri och fluorometri, före och efter seminsäsongen :

Most Swedish Warmbloods are bred by artificial insemination (AI). Quality control of the semen consists of the subjective evaluation of motility. There is a need for a more accurate and objective method of rating the semen. In this study we compared fluorometry with flowcytometry as a method for evaluating sperm viability. Semen was collected from three stallions, stationed at Markebäcks Gård, Askersund, three times during week 15 and week 34, 2008.

Laboratory tests for sperm quality and fertility in stallions

Syftet med denna litteraturgenomgång var att presentera några av de vanligast förekommandelaboratorietesterna som används idag vid utvärdering av spermakvalité hos hingstar. Engranskning har också gjorts för att försöka utröna om det går att förutse hingstars fertilitetutifrån resultaten av dessa tester. De metoder som presenteras analyserar motilitet, morfologioch funktion hos spermierna i ett ejakulat. För att kunna fullfölja en befruktning krävs det attspermien uppfyller vissa kriterier. Detta för att kunna ta sig fram till äggcellen och smältasamman med denna och bilda ett embryo.

Utvärdering av en ny selektionsmetod för hingstsperma : med avseende på membranintegriteten och membranstabiliteten

Today, equine breeding is based on performance and conformation, resulting in a vast variation in fertility among different horses, with noticeable economic losses as a consequence. The horse breeding industry is therefore in need of methods that diagnose the spermatozoa concerning their quality and provide the best sperm for AI. The commonly used selection methods for sperm today are: centrifugation, where extender is added, the sample is centrifuged and then resuspended; swim-up self-migration; adherence separation; and density gradient centrifugation. However, none of these methods are in used routinely in practice before inseminating mares with fresh or cooled semen. The aim of this study was to evaluate a new selection method, Single Layer Centrifugation (SLC), and its effect on sperm viability. The viability was analyzed with regard to membrane integrity and membrane stability of ejaculated spermatozoa.

Comparison between different freezing and thawing methods for human spermatozoa

Preservation of cells and tissues by freezing at temperatures below 70°C has led to new possibilities for the storage of germ cells for fertility preservation. During the freezing process problems might occur, the greatest being ice crystallization which can cause membrane destruction and thus cell death. To minimize this risk, solutions that reduce the freezing point can be added to reduce crystallization and increase survival rates. These solutions are called cryoprotectants. The best method for freezing is still not known.The aim of this study was to analyze the effect of various parameters on the survival rate of human semen frozen with liquid nitrogen.

Bedömning av spermiemotilitet i färsk, kyld samt selekterad hingstsperma med Qualisperm :

This EEF-project is a part of a larger project at SLU, Division of Reproduction, Dept of Clinical Science, with the intention of developing and evaluating new methods for the assessment of stallion semen quality. Over the last 10 years there has been an increase in the use of artificial insemination with cooled semen in Swedish horse breeding. At the same time, foaling rates have decreased. This has lead to a need for new and better methods of assessing the quality of stallion semen. This EEF-project was based on an objective method to calculate motility, with QualispermTM, in fresh and cooled stallion semen, and after selection. Today sperm motility evaluation is mainly done subjectively by visual assessment with a light microscope, and the correlation between these motility results and fertility have varied.

Utvärdering av viabilitet hos selekterad hingstsperma med hjälp av fluorometri :

There is considerable variation between stallions in semen quality and fertility due to the fact that selection of stallions for breeding is not based on fertility or semen quality but on performance. The increasing use of cooled semen for artificial insemination has resulted in decreasing pregnancy rates. Therefore the equine breeding industry needs new methods for evaluation and development of Sperm quality and fertility. This study is a part of such a project and is performed by SLU in cooperation with Flyinge AB. Ten stallions at the Flyinge National Stud were used in the study and three ejaculates were collected from each stallion.

Kvalitetschefens Roll och Kompetens Inom Svenska Organisationer och Företag

The role of the quality manager has evolved from being a quality controller to work with a more global business. Within many organizations in Sweden, however, the traditional role of the quality manager's remains and the tasks categorized as quality control still takes up most of the quality manager's time. The survey conducted as part of this master thesis shows that the quality manager in most businesses has multiple roles in addition to the role of quality manager, which can create a role conflict. One consequence of this is that each improvement is not given priority due to time constraints. Although the importance of a clear and committed leadership is the key for succeeding as the quality manager.

Förekomst av leukocyter i råsperma hos semingaltar :

Detection of leukocytes in semen from boars is part of the routine control of semen quality. Leukocytes in semen can cause damage to spermatozoa that leads to impaired fertilization. In the artificial insemination (AI) industry there are standard routines for the quality control of the boars and of the neat semen before use. Since 2001, Quality Genetics has not done the leukocyte examination on semen samples from boars which are used for the production of pigs for slaughter. The purpose of this study was to investigate the occurrence of leukocytes in semen from AI-boars. The questions addressed were whether there are boars that have leukocytes in their semen and how frequently it occurs and, moreover, if there are differences between breeds, or even between individuals whose semen was checked before use in AI-dose production compared to those which were not. The study included a total of 135 AI-boars, of which 67 were Hampshire, 35 Yorkshire and 33 Landrace, all belonging to Quality Genetics AI-station in Hållsta.

Systematiskt kvalitetsarbete på förskolan : Hur förskollärarna uppfattar och hanterar det systematiska kvalitetsarbetet

Systematic quality work in preschool ? How preschool teachers thinking and working with systematic quality work The purpose of this study was to investigate how Swedish preschool teachers thinking and working with systematic quality work. All Swedish preschools are required to work systematically with quality. This involves several steps that follow each other in a specific order. It includes following up, documenting and evaluating preschool activities.

Tidiga membranförändringar i hingstsperma som används för artificiell insemination :

The Annexin-V/propidium iodide (AV/PI) assay detects early membrane changes in spermatozoa and viability using flow cytometry. It is an objective method that evaluates a much larger number of single spermatozoa compared with the usual estimation of motility, the most commonly used method for routine sperm evaluation. In the present study four ejaculates from four stallions were used in a split-sample design to investigate whether and how the number of intact spermatozoa is affected over time and after incubation at different temperatures, either those recorded during shipment of stallion semen for AI (9 or 5°C) or room temperature (20°C). The Annexin-V results did not reflect the motility results that were monitored in parallel. While motility decreased over time, the number of spermatozoa with intact membranes (viable) remained unchanged for at least 21 hours following a short period of initial instability.

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