Ejaculate traits in the Namibian cheetah (Acinonyx jubatus): influence of age, season and captivity

Abstract

Abstract.The objective was to examine the influence of animal age, season and captivity status on seminal quality in wild-born cheetahs (Acinonyx jubatus) in Namibia, Africa. Animals were divided into three age categories: juvenile (14-24 months; « = 16 males, 23 ejaculates); adult (25-120 months; w = 76 males, 172 ejaculates); and aged (> 120 months; « = 5 males, 5 ejaculates). Seasons were categorised into hot-wet (January-April), cold-dry (May-August) and hotdry (September-December). A comparison between freshly wild-caught (n = 29 males, 41 ejaculates) and captive-held cheetahs (w = 68 males, 159 ejaculates) was also conducted. Raw ejaculates contained 69.0 ± 1.1% motile spermatozoa (mean ±s.e.m.) with 73.6 ± 1.5% of these cells containing an intact acrosome. Overall, 18.4 ±0.9%) of spermatozoa were morphologically normal, with midpiece anomalies being the most prevalent (~39%)) defect. Juvenile cheetahs produced ejaculates with poorer sperm motility, forward progressive status, lower seminal volume and fewer total motile spermatozoa than adult and aged animals. Spermatogenesis continued unabated throughout the year and was minimally influenced by season. Proportions of sperm malformations were also not affected by season. Ejaculates from captive cheetahs had increased volume and intact acrosomes, but lower sperm density than wild-caught counterparts. In summary, Namibian cheetahs produce an extraordinarily high proportion of pleiomorphic spermatozoa regardless of age, season or living (captive versus free-ranging) status. Young males less than 2 years of age produce poorer ejaculate quality than adult and aged males. Because (1) all study animals were wild born and (2) there was little difference between freshly caught males and those maintained in captivity for protracted periods, our results affirm that teratospermia in the cheetah is mostly genetically derived. It also appears that an ex situ environment for the Namibian cheetah can ensure sperm quality comparable with that for free-living males.

Seasonal changes in activity of males’ reproductive system in Eurasian lynx

“…We did not find such correlation in Eurasian lynx, but the lowest sperm concentration was described for the mating period when the percentage of morphologically intact sperms was at the maximum. Sperm concentration in Eurasian lynx was comparable with concentrations known for other cat species (Far-East wildcat Prionailurus bengalensis euptilurus -73 mln/ml; cheetah -22 mln/ml; Bengal cat Prionailurus bengalensis -37 mln/ml; tomcats -108 mln/ml) (Howard & Wildt, 1990;Crosier et al, 2007;Pavlova, 2010;Glukhov, Naidenko, 2013). In Eurasian lynxes sperm concentration was estimated before 0-30 mln/ml, but highly increased with the decrease of ejaculate volume (up to 540 mln/ml) .…”

Approaches and efficacy of artificial insemination in felids and mustelids

“…These cryo-tactics also have application in underdeveloped range countries, where biodiversity is especially rich [11]. For example, after conducting the prerequisite basic research [13], we have helped establish a sperm GRB for cheetahs in Namibia, a repository that represents genetic diversity of the remaining 3000 free-living cheetahs in that country [14]. Meanwhile, subsets of semen samples from the GRB are exported to support the North American Cheetah SSP [14].…”

Evidence for Compromised Metabolic Function and Limited Glucose Uptake in Spermatozoa from the Teratospermic Domestic Cat (Felis catus) and Cheetah (Acinonyx jubatus)1

“…Electronics, Boring, OR) were used to deliver 80 stimuli (at a low voltage of 2-5 V) over a 30-min interval [47]. Ejaculates (n ¼ 56 total) were collected in sterile, prewarmed vials as previously described [4,47].…”

“…The approach was unique because we took advantage of two domestic cat populations that consistently produce differing proportions of pleiomorphic spermatozoa. To increase the robustness of our findings, we conducted a cross-species comparison using the cheetah, a species that is well known to be teratospermic regardless of season or living conditions (free-range versus captive) [2][3][4]. Our hypotheses were that 1) metabolic rates are useful indicators of sperm quality in felids and 2) metabolic function is compromised in spermatozoa from teratospermic ejaculates compared to normospermic counterparts.…”

“…Species, populations, or individuals that express this condition are called teratospermic [1]. This phenomenon is especially common in species or subspecies that have low levels of gene diversity (cheetah [2][3][4], Florida panther [5,6], and Asia lion [7]) and in domestic cats that have been purposefully inbred [8]. Teratospermia (defined here as the production of !60% structurally abnormal spermatozoa) also is common among men.…”