Effect of exogenous lactoferrin and phosphoglycerate mutase 2 on the cryopreservation of wild ruminant epididymal/ejaculated sperm and testicular tissue.

Spermatozoa collected from the cauda epididymis of wild ruminants are more cryoresistant than are ejaculated spermatozoa. This work examines the effects of lactoferrin (LF) and phosphoglycerate mutase 2 (PGAM2), which are abundant in the epididymal sperm of wild ruminants, as additives in Iberian ibex and mouflon sperm extenders. In addition, LF was added to a vitrification medium to determine whether it also provided protection during the cryopreservation of testicular tissue.

Capacitation of ram spermatozoa promotes changes in energy metabolism and aquaporin 3 and is affected by individual testosterone variations.

Background: Recently, the metabolic pathways involved in energy production and the role of aquaglyceroporins in capacitation-associated events have been studied in humans and mice. However, little is known about these in ram spermatozoa.

Objective: The present study investigated bioenergetic and aquaglyceroporin 3 variations during in vitro capacitation of ram spermatozoa.

DNA integrity and viability of testicular cells from diverse wild species after slow freezing or vitrification.

Introduction And Objective: Cryopreservation of testicular tissues offers new possibilities to protect endangered species, genetically valuable individuals or even the fertility potential of prepubertal individuals who have died unexpectedly. However, the use of this technique still remains a challenge. In this study, slow freezing and vitrification of testicular tissue was investigated to find out which cryopreservation method could better preserve the viability and DNA integrity of testicular germ cells in diverse wild species.

Single or repeated immunization against GnRH fails to completely abolish spermatogenesis in dwarf bucks (Capra hircus).

In both captive wildlife and production animals is important to develop strategies for population control. Immunization against GnRH is an easy and inexpensive immunocastration method that reduces the concentration of testosterone and decreases sperm quality. However, its effectiveness depends on the species and repetition of the treatment.

Expression of Aquaglyceroporins in Spermatozoa from Wild Ruminants Is Influenced by Photoperiod and Thyroxine Concentrations.

This work identified the presence of AQPs in frozen-thawed sperm of wild ruminants and assessed the influence of the interaction between photoperiod and thyroxine on AQP expression, and on testosterone secretion. Thyroxine and melatonin were administered to ibexes. In a second experiment, performed in mouflons, circulating thyroxine was reduced via treatment with propylthiouracil (PTU), and an artificial long day (LD) photoperiod established.

Relationship between the seasonal changes in plasma testosterone and thyroxine concentrations with sperm cryoresistance in Gabon bucks.

Gabon buck is a breed with little marked seasonality in our latitude (Uruguay, 35° SL). The role of thyroid hormones on the regulation of their seasonal reproductive activity and sperm cryoresistance is unknown. Seasonal changes in testosterone concentration can affect sperm variables, but the influence of testosterone changes on sperm cryoresistance in other species determines that the recommended time for freezing sperm does not coincide with the period with greater sperm fresh quality.

Influence of circulating testosterone concentration on sperm cryoresistance: The ibex as an experimental model.

Background: Recent studies have noted that the circulating testosterone concentration may affect the ability of spermatozoa to survive cryopreservation. However, few attempts to confirm such a relationship have been made. Wild ruminant species have very marked seasonal changes in their reproductive function and strong annual changes in their plasma testosterone concentration.

Cryopreservation of ferret (Mustela putorius furo) sperm collected by rectal massage and electroejaculation: Comparison of a decelerating and an accelerating freezing rate protocol.

The domestic ferret (Mustela putorius furo) provides a good model for developing new reproductive technologies for use with threatened related species. Such technologies could also be used in the reproductive management of this pet species. The present work reports an improved freezing protocol for ferret sperm.

Seasonal variation in sperm freezability associated with changes in testicular germinal epithelium in domestic (Ovis aries) and wild (Ovis musimon) sheep.

The aim of this study was to examine ovine sperm cryoresistance during the rutting season (RS) and its association with sperm head area and seminiferous epithelium proliferation. Small ruminants show fluctuating testosterone levels throughout the year, which could interfere with spermatogenesis and sperm cryopreservation. Ejaculates, testicular biopsies and blood were collected during the middle and at the end of the RS (Middle-RS vs End-RS) during periods of high and low testosterone levels in Merino and Mouflon rams.

Recent advances in bird sperm morphometric analysis and its role in male gamete characterization and reproduction technologies.

Postcopulatory sexual selection through sperm competition may be an important evolutionary force affecting many reproductive traits, including sperm morphometrics. Environmental factors such as pollutants, pesticides, and climate change may affect different sperm traits, and thus reproduction, in sensitive bird species. Many sperm-handling processes used in assisted reproductive techniques may also affect the size of sperm cells.

Freezability of Iberian ibex (Capra pyrenaica) spermatozoa according to the glycerolization temperature and plasma testosterone concentration.

Ibex spermatozoa can be successfully frozen using glycerolated media. However, no information is available regarding the most effective method of glycerol addition in this species. The aim of the present work was to evaluate the effect of the glycerolization temperature on the response to freezing-thawing of ibex spermatozoa collected by electroejaculation.