197 SEMEN COLLECTION, TESTICULAR VOLUME, AND PRELIMINARY ASSAY OF COOLED SEMEN OF CAPTIVE PERUVIAN VICUNAS (VICUGNA VICUGNA MENSALIS)

Abstract

The vicuna (Vicugna vicugna) is a wild species of South American camelid (SAC) that lives in the Andean region from Peru to Argentina. It is classified at Low Risk by the International Union for Conservation of Nature (IUCN); however, it is a threatened species and conservation-related studies are needed. Assisted reproduction techniques are potentially useful as a conservation tool (Durrant B 2009 Theriogenology 71, 113-122), and the development of a sperm-based genome resource bank for subsequent use in AI in the vicuna is a priority. Although semen cryopreservation has been successfully applied in many species, difficulties have been encountered in SAC species. The aim of the present study was to obtain semen samples, measure testicular volume, and evaluate a protocol for cooling semen of Peruvian vicuna (V. v. mensalis). Six adult males, located at the Zoo Cerrito de la Libertad (Huancayo, Peru; n = 2), and Quimsachata Research Station (Puno, Peru; n = 4) were used. For semen collection, an electroejaculation procedure was carried out under general anesthesia. Semen was collected (n = 16) using a 2-cm-diameter probe with 3 ventral electrodes. Progressive electrical stimulation from 2 V to 12 V was applied in a protocol divided in 3 series: series 1, with 10 stimuli in 2 V, 4 V, and 6 V; series 2, with 10 stimuli in 4 V, 6 V, and 8 V; and series 3, with 10 stimuli in 10 V and 12 V. Fifteen ejaculates were collected. Semen samples (n = 6) were cooled to 4°C in egg yolk-Tris-citrate-glycerol extender and evaluated at 2, 4, 8, and 24 h. Seminal values of the ejaculates were as follows (mean ± SEM): volume = 0.85 ± 0.12 mL; pH = 7.09 ± 0.16; nonprogressive sperm motility = 28.08 ± 3.56%; sperm concentration = 166.29 ± 60.92 × 10⁴ sperm/mL; and sperm normal morphology = 62.77% ± 1.96. Testicular volume was 22.95 ± 2.28 cm³ and did not show a correlation with seminal volume and sperm concentration (r = 0.06 and r = 0.16, respectively; P < 0.05). For cooling, the extender we used was able to maintain viability for 24 h: motility = >30%, viability = >25%, and normal morphology = ≈35%. The present results demonstrate the utility of our improved electroejaculation protocol in the vicuna, and the seminal values were similar to those of a previous study (Giuliano SM et al. 2002 Theriogenology 57, 583 abst) with domestic SAC. Also, we showed that vicuna semen could be successfully cooled and stored for 24 h in an egg yolk-Tris-citrate buffered extender.

T. Huanca and M. L. Gonzáles (Quimschata Res. Stat.), G Rojas and L. Bermúdez (Huachipa Zoo), and S. Gonzáles (Zoo Cerrito de la Libertad). Reseach Supported by CONCYTEC (Fellowship to MAE).