A non‐invasive method for semen collection and evaluation in small and median size lizards

Abstract

Contents The aim of this study was to develop a non‐invasive procedure to stimulate ejaculation in median and small lizards for semen collection. After semen collection, we applied a battery of tests to assess the motility (wave and progressive), viability (eosin–nigrosin stain), morphology (normal/abnormal), sperm concentration and ejaculate number, seminal volume and colour. We obtained this fluid from all males of the four species of sceloporine lizards (n = 30) and one species of Mexican horned lizards (n = 7). We found that semen from all males had a liquid‐like consistency and a milky‐white appearance. Ejaculate volume and sperm concentration varied among the males and the species studied. We also observed that although the mobility, viability and normal sperm morphology showed a wide variability, their average value in each species was high. We conclude that “genital papilla pressure” was an efficient and non‐invasive semen obtaining method for small‐ and medium‐sized lizards that does not imply damage to donors and could be used in other lizard species.

Sperm Incubation in Biggers–Whitten–Whittingham Medium Induces Capacitation-Related Changes in the Lizard Sceloporus torquatus

“…According to morphometric values, all males (n = 15) were considered adults. We obtained semen showing consistent characteristics typical of an ejaculate [16], including volume and sperm concentration (Table 1). The data are the mean ± standard error of the mean; the range is shown in parentheses.…”

“…Semen was collected by gently pressing the genital papillae, following the method described by Martínez-Torres et al [16]. We registered the number of ejaculates, the total semen volume, and sperm concentration for each male.…”

“…To assess sperm motility, 5 µL of diluted sperm was placed on a slide and viewed under an optical microscope (Leica DM100) at 40× magnification. The percentage of active sperm was determined based on the presence of symmetrical flagellar movement, which propels them in nearly linear progressive trajectories, leading them out of the visual field [16]. It is crucial to differentiate between actively moving sperm and those passively carried away by the medium flow.…”

“…We selected Sceloporus torquatus as a model for advancing ARTs due to our understanding of its reproductive biology [14,15]. We developed non-invasive semen collection methods by establishing the time to obtain greater volumes and generated sperm quality references [16,17]. However, our efforts in sperm cryopreservation have yielded a low success rate in post-thawing recovery [18].…”

Recent Progress in Spermatology Contributing to the Knowledge and Conservation of Rare and Endangered Species

“…Alternatively, testicular macerates from recently dead amphibians provide excellent semen samples (57,58). In reptiles and birds, electrical stimulations or less invasive techniques like cloacal massaging can be used to provoke the semen secretion, which is then collected in small-diameter tubing via capillarity (59)(60)(61)(62). Lastly, in mammals, semen collection techniques (manual, electro-ejaculation, rectal massage, or epididymal flushing postmortem) depend highly on animal anatomy and size (14,63).…”