Semen

About: Semen is a research topic. Over the lifetime, 14571 publications have been published within this topic receiving 407739 citations. The topic is also known as: come & ejaculate.

Changes in sperm quality and lipid composition during cryopreservation of boar semen

Abstract: The effect of cryopreservation on boar sperm viability, motility, lipid content and antioxidant enzymatic activities was studied. Three classes of semen were determined according to a cluster analysis on the basis of the proportion of live and dead cells after freezing and thawing. The classes identified were: high (H, n = 4), average (A, n = 12) and low (L, n = 3) viability. The concentration of sperm cells decreased from class H to A to L. Fresh semen samples with higher viability and a higher proportion of motile cells also maintained better quality after the freezing and thawing procedure. Sperm viability and motility in both fresh and thawed samples were similar in classes H and A, while significantly lower values were measured in class L. The relative decrease in sperm viability and motility after cryopreservation increased from class H to A to L. The lipid content of spermatozoa (micrograms per 10(9) cells) increased significantly after freezing and thawing in classes H and A but not in class L. This result indicated that active sperm lipid metabolism might be responsible for the increase in lipid content. Phospholipid and triacylglycerol contents increased whereas free cholesterol content decreased after thawing. The fatty acid composition of fresh spermatozoa was similar in all three classes. The proportion of polyunsaturated fatty acids decreased significantly after freezing and thawing, indicating contamination from the diluent or peroxidation. After freezing and thawing, superoxide dismutase activity in spermatozoa was significantly higher in class L than in classes H and A, which did not differ from each other.

Male Fertility in Natural Populations of Red Deer Is Determined by Sperm Velocity and the Proportion of Normal Spermatozoa

Abstract: Male reproductive success is determined by the ability of males to gain sexual access to females and by their ability to fertilize ova. Among polygynous mammals, males differ markedly in their reproductive success, and a great deal of effort has been made to understand how selective forces have shaped traits that enhance male competitiveness both before and after copulation (i.e., sperm competition). However, the possibility that males also may differ in their fertility has been ignored under the assumption that male infertility is rare in natural populations because selection against it is likely to be strong. In the present study, we examined which semen traits correlate with male fertility in natural populations of Iberian red deer (Cervus elaphus hispanicus). We found no trade-offs between semen traits. Our analyses revealed strong associations between sperm production and sperm swimming velocity, sperm motility and proportion of morphologically normal spermatozoa, and sperm viability and acrosome integrity. These last two variables had the lowest coefficients of variation, suggesting that these traits have stabilized at high values and are unlikely to be related to fitness. In a fertility trial, our results show a large degree of variation in male fertility, and differences in fertility were determined mainly by sperm swimming velocity and by the proportion of morphologically normal sperm. We conclude that male fertility varies substantially in natural populations of Iberian red deer and that, when sperm numbers are equal, it is determined mainly by sperm swimming velocity and sperm morphology. acrosome reaction, gamete biology, male reproductive tract, sperm, sperm motility and transport

Catalase activity in human spermatozoa and seminal plasma.

Abstract: Catalase activity was determined in human semen by measuring the oxygen burst with a Clark electrode, after H2O2 addition. Significant catalase activities (mean +/- SD) were found in migrated, motile spermatozoa (44 +/- 17 nmoles O2/min/10(8) cells) and in seminal plasma of normozoospermic men (129 +/- 59 nmoles O2/min/ml). It has been demonstrated that seminal catalase originated from prostate; however, its activity was not correlated with the usual prostatic markers (such as citric acid and zinc). Our data suggest a multiglandular function secreted by this organ. The catalase activities measured in seminal samples from asthenozoospermic, infertile men were found lower than those from normozoospermic subjects. The understanding of the relative contribution of the different enzyme systems against O2 toxicity (superoxide dismutase, catalase, glutathione peroxidase) seem to be a priority area of research to understand disturbances of sperm function.

The biochemistry of semen.

Abstract: Workers in the field of semen chemistry and physiology (and they now include a substantial number of biochemists, clinicians, zoologists, and veterinarians) will be greatly indebted to Dr. Mann for having written this treatise with masterly skill. The information which it compresses into a very modest compass is culled from numerous sources, the majority of which are comparatively inaccessible, and the bibliography of nearly a thousand items speaks eloquently for the completeness of this survey. To the writing of this book Dr. Mann has brought not only his authoritative knowledge of the subject, a clarity of expression, and preciseness, but also a conspicuous degree of scholarship. No better choice of author could be conceived for this contribution to the series of monographs on biochemical subjects published by Methuen. The book begins with an account of the main structural and physiological features of spermatozoa and the accessory glands, and proceeds with a' detailed description of the physical and chemical properties of semen and of the methods used for the evaluation of its quality. A particularly happy feature is the inclusion of much comparative data from many mammalian as well as non-mammalian species. Next, the influence of extraneous factors-hormones, sperm-egg interacting substances, spermicidal agents, sperm dilutors, ionizing radiations, and deep freezingreceives consideration. Later chapters deal with metabolic processes which supply the spermatozoa with energy for their motility and survival. The identification of the sugar of seminal plasma as fructose was one of Dr. Mann's numerous original contributions to this subject, and it is therefore fitting that this substance, its secretion by the accessory glands, and its metabolism by spermatozoa, should receive special attention. Other chapters discuss the occurrence of inositol, lipids, and citric acid; nitrogenous bases including spermine, choline, and ergothioneine; and the protein constituents and enzymes of spermatozoa and seminal plasma. This book ought to be in the possession of anyone who in any way is concerned with animal reproduction.