195 Evidence of Seasonality in Semen Characteristics of Captive Andean Hairy Armadillo (Chaetophractus Nationi)

Abstract

Chaetophractus nationi is an armadillo species that inhabits in the high Andes of Peru, Chile, and Bolivia at altitudes of over 3000 m. The main threats to this species are habitat loss and over-hunting; in the last 10 years it has been estimated that the population has declined by 30%. The species is categorized as Vulnerable (VU, A2d) by International Union for Conservation of Nature (IUCN) and Peruvian legislation (DS-034-2004-AG) and is listed in appendix II of Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Chaetophractus nationi is 1 of 7 species of armadillos in which further studies on their reproductive biology and physiology are considered to be urgently needed. The aim of the present study was to determine the semen ejaculate values of C. nationi males in 2 opposite seasons. Six adult males of C. nationi belonging to the Huachipa Zoological Park (Lima, Peru) collection under the same captive conditions were used. Semen samples were collected coinciding with the Peruvian warm season (February) and cold season (June). The animals were chemically immobilized using ketamine (15 mg kg-1), xylazine (1 mg kg-1), and midazolam (0.4 mg kg-1) i.m. Semen was collected by an electroejaculation technique using commercial equipment (Eletrojet®, Eletrovet, São Paulo, Brazil) and a rectal probe specifically designed in Peru for the species. Progressive electrical stimulation from 2 to 6 V was applied in a protocol of 30 stimuli divided into 3 series: series 1, with 10 stimuli of 3 sec at 2 V; series 2, with 10 stimuli of 3 sec at 4 V; and series 3, with 10 stimuli of 3 sec at 6 V The results (mean ± SEM) for the warm season (26-28°C) were n = 6; volume = 80 ± 10.34 μL; pH = 8.2 ± 0.3; progressive motility = 77% ± 0.06; and sperm concentration/mL = 46.2 ± 2.9 × 106. The results (mean ± SEM) for the cold season (13-18°C) were n = 6; volume = 8.6 ± 2.27 μL; pH = 8.7 ± 0.18; and progressive motility = 80%. Sperm concentration could not be determined on the cold season samples because of the low volume collected. In summary, our results are suggestive of a seasonal pattern in semen characteristics of the Andean hairy armadillo that may be related to its reproductive activity in the wild. J. Pino and B. Shiga (UNMSM), for help with the rectal probe elaboration.