Spermatology for understanding, managing and conserving rare species

Abstract

Abstract. Most conventional spermatology research involves common mammalian species including livestock, laboratory animals and humans. Yet, there are more than 4500 mammalian species inhabiting the planet for which little is known about basic reproductive biology, including sperm characteristics and function. This information is important, not just as adjunct knowledge, but because the majority of these species are threatened with extinction, largely due to human-induced pressures. The field of conservation is changing rapidly, and global cooperation is emerging among a variety of wildlife enthusiasts, ranging from management authorities of nature reserves to curators of rare zoological collections. Conservation progress depends on systematic, multidisciplinary research first to answer basic questions, with new data then applied to endangered species management plans. The reproductive physiologist is a crucial component of this scheme. Reproduction is the essence of species survival, and enormous effort needs to be directed at these 'untraditionaP research species, subspecies and populations. Spermatology research combined with simultaneous efforts in endocrinology, embryology and cryopreservation (among others) can lead to the successful application of assisted reproduction. Examples from this laboratory include an array of wild fetid species and a rare cervid and mustelid. Obstacles to success are formidable, including unique species-specificities, diminished genetic diversity and a general lack of resources. Nonetheless, the field offers tremendous opportunities for generating unique knowledge of comparative interest and with conservation utility.

Cryopreservation of spermatozoa from wild-born Namibian cheetahs (Acinonyx jubatus) and influence of glycerol on cryosurvival

“…The wild cheetah oYcially is recognized as threatened with extinction [3], primarily due to habitat fragmentation and agricultural encroachment [20,21,23]. This disassembly of habitat results in small, isolated populations that are especially vulnerable to loss of gene diversity which in turn causes reproductive compromise and susceptibility to catastrophes, including disease [41,42]. The cheetah is well recognized for its comparatively low genetic variation [25,26] and its diYculty of reproducing in captivity [18].…”

Approaches and efficacy of artificial insemination in felids and mustelids

“…1) [3,35,36]. Our laboratory has revealed that 20 of the 23 felid species (or their subspecies) evaluated consistently experienced this condition (range, 4-58% normal sperm; Fig.…”

“…Ex situ breeding programs exist for many of these rare carnivores, and one of the highest priorities is the retention of existing gene diversity to ensure species integrity, health and reproduction. Tools associated with 'assisted reproduction' offer multiple advantages for species propagated under the auspices of an organized genetic management plan (e.g., the Species Survival Plan or SSP#; Table 1) [2,3]. Because cooperating institutions (usually zoos) breed animals on the basis of the genetic value of individuals and computerized calculations of kinship (i.e., interrelatedness) [4], the general protocol commonly involves physically moving animals between geographically different zoos for breeding.…”

“…Initial activities emphasized applying cattle and human AI techniques directly to wildlife. When such a naïve, overly simplistic approach failed [3,7], we re-designed strategies to develop a thorough knowledge base for each targeted species of interest. Once the reproductive physiology of each species was better understood (generally over the course of years), then positive AI-related results emerged [8][9][10].…”

Intersexuality in a crab-eating fox (Cerdocyon thous)

“…Nonetheless, in recent years, the number of intersexuality case reports has been growing in wild animals (EPA 1997). Some researchers have hypothesized that this condition might be due to environmental contamination, mainly by endocrine-disrupting chemicals (EPA 1997, Wiig et al 1998, Brunstrom & Halldin 2000, or by effects of habitat loss and fragmentation on wild animal genetic variability and reproduction (Wildt et al 1995, Jobling et al 2002, Lukas & Walter 2002. However, to associate abnormal sexual differentiation to the environmental factors still difficult and must remain, in many cases, as suggestive etiology.…”