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Topic:Sperm
Equine sperm refers to the male reproductive cells produced by stallions, essential for the process of fertilization and successful breeding in horses. The study of equine sperm encompasses various aspects, including morphology, motility, viability, and genetic integrity. These parameters are critical for assessing stallion fertility and improving breeding outcomes. Research in this field often focuses on understanding the factors that influence sperm quality, such as age, nutrition, and environmental conditions. Additionally, advancements in assisted reproductive technologies, such as artificial insemination and cryopreservation, rely heavily on the detailed study of sperm characteristics. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, evaluation, and technological applications related to equine sperm.
Capacitation-like changes in equine spermatozoa following cryopreservation. The primary objective of this study was to assess plasma membrane characteristics and activation of signal transduction pathways in equine spermatozoa during both in vitro capacitation and cryopreservation. Significant plasma membrane restructuring, as assessed by measurement of plasma membrane lipid disorder and phospholipid scrambling, was not observed until after cryopreservation and subsequent thawing (P < 0.05). Although in vitro capacitated cells also displayed increased plasma membrane lipid disorder and phospholipid scrambling (P < 0.05), it appeared that regulation of these even...
Proopiomelanocortin gene expression and beta-endorphin localization in the pituitary, testis, and epididymis of stallion. Proopiomelanocortin (POMC) is a precursor protein that contains the sequences of several bioactive peptides including adrenocorticotropin (ACTH), beta-endorphin (beta-EP), and melanocyte-stimulating-hormone (MSH). POMC is synthesized in the pituitary gland, brain, and many peripheral tissues. Immunoreactive POMC-derived peptides as well as POMC-like mRNA have been evidenced in several nonpituitary tissues, thus suggesting that POMC is actively synthesized by these tissues. The present study was aimed at evaluating if also in the case of stallion POMC-derived peptide, beta-EP, is produced local...
Determination of glutathione peroxidase and superoxide dismutase-like activities in equine spermatozoa, seminal plasma, and reproductive tissues. To determine glutathione peroxidase (GPX) and superoxide dismutase (SOD)-like activities in spermatozoa, seminal plasma, and reproductive tissues (ie, testis, epididymis, bulbourethral gland, prostate, vesicular gland, and ampulla) in horses. Methods: Seminal plasma from 17 stallions, spermatozoa from 5 stallions, and reproductive tissues from 3 stallions. Methods: Activity of GPX was determined by use of assays measuring oxidation of NADPH in the presence of exogenous glutathione, cumene hydroperoxide, and glutathione reductase. Activity of SOD-like enzymes was determined by use of the nitrob...
Equine spermatozoal motility and fertility associated with the incorporation of d-(+)-mannose into semen extender. Mannose is capable of decreasing bacterial attachment to the uterine mucosa in mares. Bacteria gain entry into the mare's uterus during breeding; therefore, a practical method to deliver mannose to the uterus is to incorporate it into semen extenders. The effect of mannose on spermatozoal motility and subsequent sperm fertilizing capability is unknown. The present study evaluated progressive spermatozoal motility in semen extender formulations incorporating mannose and assessed the fertility of mares inseminated with a mannose-containing semen extender. In Experiment 1, progressive spermatozoa...
The sperm chromatin structure assay: a review of clinical applications. The sperm chromatin structure assay (SCSA) was introduced by as a method to determine the susceptibility of sperm DNA to denaturation and how those results related to fertility. This initial study used human sperm and was followed by studies in bulls and boars . This assay was one of the first to introduce the technique of flow cytometry, which has the ability to evaluate specific sperm compartments of large numbers of sperm in a short time, as a methodology to evaluate sperm quality and further define the relationship of sperm quality to fertility. For any assay to be of use clinically, it mu...
The role of stallion seminal proteins in fertilisation. Seminal plasma proteins are secretory proteins originating mainly from the epididymis and the accessory sex glands. They are involved in the remodelling of the sperm surface which occurs during sperm transit through the male genital tract and continues later at ejaculation. During this process, collectively called post-testicular sperm maturation, the spermatozoa acquire the ability to fertilise an egg. Seminal plasma proteins have been shown to contribute to early and central steps of the fertilisation sequence, e.g. the establishment of the oviductal sperm reservoir, modulation of capacitati...
Adding cholesterol to the stallion sperm plasma membrane improves cryosurvival. Cryopreservation induces partially irreversible damage to equine sperm membranes. Part of this damage occurs due to membrane alterations induced by the membrane changing from the fluid to the gel-state as the temperature is reduced lower than the membrane transition temperature. One way to prevent this damage is to increase the membrane fluidity at low temperatures by adding cholesterol to the membrane. Different concentrations of cholesterol-loaded-cyclodextrins (CLC) were added to stallion sperm to determine the CLC concentration that optimizes cryosurvival. Higher percentages of motile sper...
French field results (1985-2005) on factors affecting fertility of frozen stallion semen. Results on procedures for freezing stallion semen and the subsequent fertility during 20 years are presented. The present system applied in French National Stud includes: (1) a freezing protocol (dilution in milk, centrifugation and addition of freezing extender (INRA82+egg yolk (2%, v/v)+glycerol (2.5%, v/v) at 22 degrees C, a moderate cooling rate to 4 degrees C and freezing at -60 degrees C/min in 0.5-ml straws); (2) selection of ejaculates showing post-thaw rapid motility >35%; and (3) an insemination protocol (mares examined once daily, two AI of 400 x 10(6) spermatozoa 24 h apart befo...
Components in seminal plasma regulating sperm transport and elimination. Seminal plasma has been suggested to be involved in sperm transport, and as a modulator of sperm-induced inflammation, which is thought to be an important part of sperm elimination from the female reproductive tract. This article reports on recent experiments on the importance of seminal plasma components in sperm transport and elimination. In Experiment 1, hysteroscopic insemination in the presence (n = 3) or absence (n = 3) of 2 ng/mL PGE showed an increased portion of spermatozoa crossing the utero-tubal junction in the presence of PGE in two mares, while no difference was observed between ...
Equine blastocyst development after intracytoplasmic injection of sperm subjected to two freeze-thaw cycles. This study was conducted to evaluate the effects of thawing, division into aliquots and refreezing on fertilizing capacity (ability to support embryo development after intracytoplasmic sperm injection; ICSI) of frozen stallion semen. Frozen semen from a fertile stallion was thawed, diluted 1:100 with freezing extender, and refrozen (2F treatment). Control semen was frozen only once. In vitro matured equine oocytes were injected with: (1) motile control spermatozoa; (2) motile 2F spermatozoa; (3) non-motile 2F spermatozoa; or (4) non-motile 2F spermatozoa, followed by injection of sperm extract...
Challenges facing sex preselection of stallion spermatozoa. Since the production of the first live offspring from sex-sorted spermatozoa in 1989, there have been many developments in the fluorescence-activated cell separation (FACS) procedures to preselect X- and Y-chromosome bearing spermatozoa prior to insemination. During this time, FACS technology has been applied to a range of species and has resulted in offspring from rabbits, cattle, sheep, elk and horses. In horses, satisfactory fertility rates have been achieved after hysteroscopic insemination of 20 x 10(6) fresh or stored, sex-sorted spermatozoa. However, many of the sperm processing protoco...
Factors affecting the plasma membrane function of cooled-stored stallion spermatozoa. The spermatozoon is a highly specified cell that has the abilities of active motility and fertilization of the ovum. Damage to the sperm plasma membrane results in the irreversible loss of its functions. Because of the high content of unsaturated fatty acids in the plasma membrane, mammalian sperm are sensitive to oxidative stress. While mild peroxidation appears to promote capacitation of the sperm cell, excessive peroxidation will damage the plasma membrane and results in loss of motility and fertility. The functional integrity of the sperm plasma membrane can be determined by functional tes...
Effect of the inseminate and the site of insemination on the uterus and pregnancy rates of mares. In this review, effects of the composition of the inseminate on uterine response and pregnancy rates in mares are discussed. The inseminate can differ for volume, sperm concentration, total sperm numbers, presence, absence, or proportion of seminal plasma, and extender composition. Semen can be used as fresh, cooled, or frozen. The site of semen deposition also plays a role; semen is deposited either into the uterine body (standard artificial insemination (AI)) or into the tip of the uterine horn ipsilateral to the preovulatory follicle (deep AI) using the hysterocopical or transrectally guide...
Genetic markers for stallion fertility–lessons from humans and mice. Our knowledge on the many aspects of mammalian reproduction in general and equine reproduction in particular has greatly increased during the last 15 years. Advances in the understanding of the physiology, cell biology, and biochemistry of reproduction have facilitated genetic analyses of fertility. Currently, there are more than 200 genes known that are involved in the production of fertile sperm cells. The completion of a number of mammalian genome projects will aid in the investigation of these genes in different species. Great progress has been made in the understanding of genetic aberrati...
