Study of semen parameters in captive brown bears (Ursus arctos)

Abstract

As the Carpathian brown bear still represents one of the biggest populations of bears across Europe, the study of its semen parameters as well as cryopreservation can help advancing the research regarding conservation of genetic diversity for the endangered sub-species of European brown bear. The aim of this paper was to study the parameters of the Carpathian brown bear semen and to attempt its liquid storage at 4°C. The study was performed on two bears, one belonging to the Turda zoo and another to the Libearty bear sanctuary in Zarnesti. We obtained one sample of semen by electro-ejaculation from an 18 years old captive brown bear from the Turda zoo, while the Libearty bear sanctuary provided us with a pair of testicles from a 2.2 years old male, from which we obtained semen by retrograde flushing of the epididymis. We analyzed those samples in 2 different extenders, before and after 24h refrigeration, using the CASA system for concentration and motility and the flow-cytometer for viability. The results showed that semen obtained by electro-ejaculation had good motility, which decreased after 24h of refrigeration, while viability was adequately maintained. The epididymal extraction also provided semen with high motility and viability, but liquid storage at 4°C was unsuccessful. This study is just a beginning, as it needs to be further continued, in order to reach the goal of creating a sperm bank for the Carpathian brown bear and offer new data that could help the preservation of endangered populations of other European brown bears.