Polyandry is a common mating strategy in animals, with potential for sexual selection to continue post-copulation through sperm competition and/or cryptic female choice. Few studies have investigated the influences of population density on polyandry and sperm usage, and paternity distribution in successive broods of marine invertebrates. The marine gastropod Rapana venosa is ideal for investiga...

BACKGROUND In assisted reproduction procedures, we need to develop and enhance new protocols to optimize sperm selection. The aim of this study is to evaluate the ability of the Z potential technique to select sperm with intact DNA in non-normospermic patients and evaluate the impact of this selection on embryonic development. METHODS We analyzed a total of 174 human seminal samples with at l...

Across species, there is usually a positive relationship between sperm competition level and male reproductive effort on ejaculates, typically measured using relative testes size (RTS). Within populations, demographic and ecological processes may drastically alter the level of sperm competition and thus, potentially affect the evolution of testes size. Here, we use longitudinal records (across ...

In the present study, the effect of successive milt collection was investigated on spermatological parameters and reproduction successes of wild and cultured endangered caspian brown trout. The milt collection was done 3 times with two weeks intervals. After milt collection, amount of milt was allocated for milt quality evaluation and reminders used for fertilization. According to results, in w...

Background Sperm DNA fragmentation is known as an important cause of male infertility. The influence of sperm DNA damage on reproductive potential has been subject of many studies indicating various results and remaining the subject controversial. In this study, we investigated differences of the semen parameters and intracytoplasmic sperm injection (ICSI) outcome according to sperm DNA fragmen...

OBJECTIVE:We evaluated the effectiveness of spermwashing using the discontinuous two-layer density gradient centrifugation method to remove antisperm antibodies attached to the sperm surface. METHOD: We prospectively enrolled sixty-six men with unexplained infertility who were seeking evaluation. Each patient delivered one semen specimen for the study. We determined antisperm antibody levels us...

Previous studies of the associations of measures of occupational lead exposure with measures of semen quality and infertility among male workers have produced conflicting results. The current study was undertaken to examine these associations among a population of workers with a broad range of measures of current and historical lead exposure. Ninety-seven lead-exposed workers from a South Afric...

Studies showed that assisted reproductive technology changed the sex ratio at birth, but the effect of semen processing (swim-up technique and density-gradient separation) on enriching either Xor Y-bearing sperm is always controversial. We recruited 30 healthy males and their semen samples were obtained by masturbation after sexual abstinence for 2-7 days. Each sample was divided into 3 aliquot...

Although alternative mating tactics are found in males of many species, little is known about tactic-specific adaptations to sperm competition and the mechanism by which fertilization success is obtained. We now report on the sperm investment patterns of males that use alternative mating tactics in bluegill sunfish (Lepomis macrochirus). Bluegill males are characterized by three alternative mat...

In this study, quantitive characteristics and chemical composition of in roach (Rutilus rutilus caspicus) sperm were investigated. Sperm traits included sperm movement duration, percentage of motile spermatozoa, sperm density, spermatocrit and sperm volume. Some seminal plasma characteristics (sodium, potassium, calcium, magnesium and chloride) were investigated. In addition, some metabolites o...