Fertility in the male is dependent on the proper production of sperm cells. This process, called spermatogenesis is very complex and involves the synchronization of numerous factors. The presence of pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-α), interleukin-1 alpha (IL-1 α) and interleukin 1 beta (IL-1 β) cytokines in the male reproductive tract (testis, epididymis and sperm) ...

Transgenic modification of sperm before fertilization has distinct advantages over conventional transgenic methods. The primary advantage is that the mosaicism inherent in those other techniques is avoided. A culture system using primary cultures of zebrafish male germ cells, in which the differentiation from spermatogonia to functional sperm can occur in vitro, provides the opportunity for gen...

Sex allocation theory for simultaneous hermaphrodites has focused primarily on the effects of sperm competition, but the role of mate choice has so far been neglected. We present a model to study the coevolution of cryptic female choice and sex allocation in simultaneous hermaphrodites. We show that the mechanism of cryptic female choice has a strong effect on the evolutionary outcome: if indiv...

Male infertility has been found to be a major factor in a couple’s inability to conceive in 50% of childless marriages. There are many causes of male infertility including: deficient sperm production, blockage of ducts through which sperm are transported from the testicles, hormonal abnormalities, failure of sperm to mature properly and antisperm antibodies. Varicocele is felt to play a major r...

Artificial insemination (AI) is the preferred method for reproduction in the majority of the intensive pig production systems Worldwide. To this end, fresh extended ready-to-use semen doses are either purchased from AI-centres or produced by boars kept on-farm. For profitable semen production, it is necessary to obtain a maximum amount of high quality semen from each boar. This paper reviews cu...

Introduction The reproductive efficiency of the breeding herd depends upon the fertility of the boar. Male fertility is essential since the boar's DNA is the primary mechanism through which genetic improvements can efficiently be accomplished. In production settings, the critical event, which begins the reproductive process, is the meeting of sperm and eggs inside the female reproductive tract....

Acrosin activity and semen quality (sperm concentration, ejaculate volume and number of spermatozoa) were assessed from March 1997 to March 1998 in semen of Large White, Pietrain and Duroc x Pietrain boars. Semen quality varied with season, including high production of spermatozoa in autumn and winter and low production in summer. Semen quality also differed across breeds. Acrosin activity of b...

Males that follow alternative reproductive tactics might differ in their investment into testis development and sperm production. The resource-allocation hypothesis predicts that males following a sneaker tactic should invest more into sperm production than dominant territorial males which should invest more into mate guarding. This hypothesis is supported by studies in species where individual...

The sperm DNA damage may occur in testis, genital ducts, and also after ejaculation. Mechanisms altering chromatin remodeling are abortive apoptosis and oxidative stress resulting from reactive oxygen species. Three classifications of intratesticular, post-testicular, and external factors have been correlated with increased levels of human sperm DNA damage which can affect the potential of fert...

Organisms that reproduce by sperm-dependent parthenogenesis are asexual clones that require sperm of a sexual host to initiate egg production, without the genome of the sperm contributing genetic information to the zygote. Although sperm-dependent parthenogenesis has some of the disadvantages of sex (requiring a mate) without the counterbalancing advantages (mixing of parental genotypes), it ap...