The introduction of the technique of intracytoplasmic sperm injection to achieve fertilization, especially using surgically retrieved testicular or epididymal sperm from men with obstructive or non-obstructive azoospermia, has revolutionized the field of assisted reproduction. The techniques for the retrieval of spermatozoa vary from relatively simple percutaneous sperm aspiration to open excis...

Costs incurred in the manufacture of ejaculates may constrain the number of sperm that males can produce, so males should show some economy in their allocation of sperm across multiple matings. In species in which females mate with multiple males and are capable of storing sperm for extended periods, sperm allocation of males should be tailored to the risk of sperm competition. Recent game theo...

The outcome of sperm competition (i.e. competition for fertilization between ejaculates from different males) is primarily determined by the relative number and quality of rival sperm. Therefore, the testes are under strong selection to maximize both sperm number and quality, which are likely to result in trade-offs in the process of spermatogenesis (e.g. between the rate of spermatogenesis and...

BACKGROUND Many factors may lead to sperm DNA damage. However, it is little known that the correlations of sperm DNA damage with obesity-associated markers, and reproductive hormones and lipids levels in serum and seminal plasma. METHODS In our prospective study, a total of 1 010 subfertile men, aged from 18 to 50 years old, were enrolled from August 2012 through June 2015. Their obesity-asso...

In the game of evolutionary fitness, males must maximize the chance that their sperm successfully fertilize oocytes. Speciesspecific strategies include making more, bigger, or faster sperm, or producing seminal fluid that does more than serve as a vehicle for sperm transfer [1]. Importantly, seminal fluid components not only modulate sperm function and promote their competitiveness and long-ter...

Sperm competence in animal fertilization requires the collective activities of numerous sperm-specific proteins that are typically alloimmunogenic in females. Consequently, sperm membrane alloantigens are potential targets for contraceptives that act by blocking the proteins' functions in gamete interactions. Here we used a targeted proteomics approach to identify the major alloantigens in swin...

Damage occurring to spermatozoa during cryopreservation results in a loss of motile cells and cells that are functionally normal, compared with fresh sperm samples. Treating bull sperm with cholesterol-loaded cyclodextrins (CLC) before cryopreservation results in increased sperm cryosurvival. However, in previous studies, CLC were always added to sperm samples that had been highly diluted. The ...

Past studies have suggested that mouse sperm surface galactosyltransferase may participate during fertilization by binding N-acetylglucosamine (GIcNAc) residues in the zona pellucida. In this paper, we examined further the role of sperm surface galactosyltransferase in mouse fertilization. Two reagents that specifically perturb sperm surface galactosyltransferase activity both inhibit sperm-zon...

Sperm competition, the contest among ejaculates from rival males to fertilize ova of a female, is a common and powerful evolutionary force influencing ejaculate traits. During competitive interactions between ejaculates, longer and faster spermatozoa are expected to have an edge; however, to date, there has been mixed support for this key prediction from sperm competition theory. Here, we use t...

Hyaluronidase release was used as an index of acrosomal membrane damage during cold shock of epididymal boar sperm and ejaculated sperm from intact and vesiculectomized boars. Sperm were also incubated with seminal plasma from intact and vasectomized boars to examine the contributions of male accessory gland secretions. Acrosomal membranes of epididymal sperm were more resistant to cold shock t...