نتایج جستجو برای: sperm production
تعداد نتایج: 638025 فیلتر نتایج به سال:
Bull fertility may be defined as the process by which spermatozoa fertilize and activate the ovum and then support embryonic development. Bull fertility is a complex trait having relatively low heritability and plays a vital role for efficient production and reproduction of bovine. Various mechanisms involved in regulating bull fertility associated phenotype and reliable biomarkers are poorly d...
The study evaluated the protective effect of seminal plasma (SP) added to freezing extender against cryopreservation injuries to boar spermatozoa. Pooled sperm-rich fractions collected from 9 fertile boars were frozen in 0.5-mL straws after being extended in a conventional freezing extender either alone or supplemented with 5% of SPs (SP1-SP4) collected from the sperm-rich fractions (diluted 1:...
We have previously shown that polymorphonuclear neutrophils (PMNs) are present in bovine oviduct fluid under physiological conditions, and that the oviduct provides a microenvironment that protects sperm from phagocytosis by PMNs. Alpha 1-acid glycoprotein (AGP) is a major acute-phase protein produced mainly in the liver that has immunomodulatory functions. AGP mRNA is expressed in extrahepatic...
Climate change alters the thermal habitat of aquatic species on a global scale, generating novel environmental challenges during all life stages, including reproduction. Changes in water temperature profoundly influence the performance of ectothermic aquatic organisms. This is an especially crucial issue for migratory fish, because they traverse multiple environments in order to reproduce. In e...
Aim of the present study is to investigate the total antioxidant capacity (TAC) and lipid peroxidation end product, malondialdehyde (MDA) concentration in seminal plasma of fertile and infertile men and its relationship with different spermatozoa parameters. Semen samples were collected from 15 fertile men (normozoospermic as control) and 40 infertile men (15 oligozoospermic, 17 asthenozoosperm...
background: nitric oxide (no) is synthesized from l-arginine by a family of enzymes known as nitric oxide synthases. low concentrations of no is essential in biology and physiology of spermatozoa, but high amounts of no is toxic and has negative effects on sperm functions. moreover, sperm membrane contains high concentrations of polyunsaturated fatty acids that are highly susceptible to oxidati...
objective: to study the morphology ofgonads and sperm ducts of sex reversed male rainbow trout after administration of i 7-cr- methyl testosterone. animals: rainbow trout, oncorhynchus mykiss. procedure: l7-alpha-methyl testosterone (17-alpha-mt) was administered to rainbow trout in 5 treafinents as follows: i) rwo times immersion of eyed eggs and yolk sac alevins in 250 pg/l bath with 2 hours ...
BACKGROUND Declining fertility of couples from the fourth decade of life is largely attributable to the drop in female fertility. However, increasing numbers of men, whose fertility theoretically lasts until death, are seeking fertility treatment at older ages, yet there is little information on sperm production and function past the age of 50 years. The few studies of such older men have exami...
A turkey hen in egg production requires 48 h after the last insemination to maximize the number of sperm in the uterovaginal junction sperm-storage tubules. Where the sperm that continue to fill the oviductal sperm-storage sites during this 48-h period reside remains unknown. Histological sections of the juncture of the vagina with the urodeum, the central compartment of the cloaca, revealed de...
Effect of male age on sperm traits and sperm competition success in the guppy (Poecilia reticulata).
Deleterious mutations can accumulate in the germline with age, decreasing the genetic quality of sperm and imposing a cost on female fitness. If these mutations also affect sperm competition ability or sperm production, then females will benefit from polyandry as it incites sperm competition and, consequently, minimizes the mutational load in the offspring. We tested this hypothesis in the gupp...
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