Electroejaculation and semen characteristics of Asiatic Black bears (Ursus thibetanus)

The development of sperm cryopreservation procedures in brown bear is the basis for establishing a specific genetic resource bank aimed at the preservation of a Cantabric brown bear population, which is seriously threatened. Several issues complicate the development of these cryopreservation procedures: lack of previous specific studies, a high incidence of urospermia and spermagglutination observed in bear ejaculates. Moreover, the availability of individuals for research from these threatened populations is problematic. In the case of the Cantabric brown bear, we have used males from other populations, but of the same species, as surrogates, to carry out a direct extrapolation of the results. Urospermia-- Moreover, 70% of the ejaculates are urine contaminated and spermagglutination have a detrimental effect on post-thawing cell quality recovery in this species. Considering the high value of these samples (autochthonous population with few individuals), a pre-selection of the ejaculates is not a viable alternative. Preventive methods reducing the mentioned detrimental effects need to be developed. On the basis of previous data, we can suppose that bear spermatozoa resist freezing injuries well. Nevertheless, because of the scarcity of this information, it is necessary to conduct further research on bear semen freezing under field conditions. Epidydimal spermatozoa can be important for genetic resource banking of threatened populations and thus specific cryobiological protocols need to be assayed. To date, 168 brown bear ejaculates have been frozen by the ITRA-ULE group at the University of León (Spain) in the development of methodologies for the preservation of brown bear sperm.

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“…In most publications, bears are immobilized under captive conditions. The use of ketamine (10–15 mg/kg Chen et al. 2007; 7 mg/kg Zhang et al.…”

Section: Challenges In Obtaining and Working With Brown Bear Electroementioning

confidence: 99%

Sperm Cryopreservation in Brown Bear (Ursus arctos): Preliminary Aspects

Anel

Álvarez

Martínez‐Pastor³

et al. 2008

Reprod Domestic Animals

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“…Spontaneous contamination of ejaculates with urine occurs frequently in many species (horse, Althouse et al, 1989;man, Chen et al, 1995). In some species, the urine contamination occurs when the sample is obtained by electroejaculation (bear: Kojima et al, 2001;Okano et al, 2004;Chen et al, 2007;Anel et al, 2008;felines: Pukazhenthi et al, 2000;Iberian ibex: Santiago-Moreno et al, 2011). An elevated incidence of urine contamination in ejaculates had been reported (brown bear: Anel et al, 2008; Japanese black bears: Kojima et al, 2001 andOkano et al, 2004; Asiatic black bears: Chen et al, 2007).…”

Section: Introductionmentioning

confidence: 98%

Salvaging urospermic ejaculates from brown bear (Ursus arctos)

Gomes-Alves

Álvarez

Nicolás

et al. 2014

Animal Reproduction Science

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“…Different studies on electroejaculation of bears have indicated an elevated incidence of urospermia, with the consequent loss of semen quality (Okano et al 2004;Chen et al 2007;Kojima et al 2001;Anel et al 2008). Thus, we considered that developing a protocol for washing sperm samples was critical for the success of a sperm recovery plan in the brown bear.…”

Section: Discussionmentioning

confidence: 97%

“…Some species such as the bear (Kojima et al 2001;Chen et al 2007;Anel et al 2008) may yield semen contaminated by the urine during electroejaculation. A usual method for counteracting the noxious effect of urine contamination is to add large volumes of extender to the contaminated sample and centrifuge it immediately, removing the supernatant and substituting it with clean medium (Makler et al 1981;Kim and Kim 1998).…”

Section: Introductionmentioning

confidence: 99%

Effects on brown bear (Ursus arctos) spermatozoa freezability of different extender and dilution ratios used for pre-freezing centrifugation

et al. 2010

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The objective of this study was to determine how the extender and dilution ratio used during centrifugation affect bear spermatozoa quality before and after freezingthawing. Semen was collected from 15 brown bears by electroejaculation. In experiment 1, semen was divided into five aliquots and diluted using one of the following extenders: Tris-citric-glucose (TCG), Tris-citric-glucose-3% BSA, Tris-citric-glucose-1% egg yolk or CaninePro. In experiment 2, semen was divided into five aliquots and diluted 1:1, 1:4, 1:8 or 1:16 (semen:extender) with Triscitric-glucose. In both experiments, one aliquot was left undiluted and it was used as a control. All the aliquots were centrifuged at 600×g for 6 min and frozen. Samples were analysed by post-thawing for motility (CASA) and, by flow cytometry, for viability (YO-PRO-1), acrosomal status (PNA-FITC/PI) and mitochondrial status (JC-1). CaninePro rendered the highest motility with respect to the undiluted control (total motility, 53.1% vs. 38.5%, P<0.001), and CaninePro and TCG significantly increased the percentage of viable and acrosome-intact spermatozoa (43.2 and 43.4, respectively, vs. 39.4, P<0.05). In experiment 2, dilution 1:4 yielded the highest value of total motility (78.8 vs. 67.2, P<0.05) and proportion of spermatozoa with intact membrane and acrosome (64.5 vs. 54.4, P<0.01). In general, diluting 1:4 or 1:8 brown bear semen prior to centrifugation improved the motility and acrosome status of the thawed spermatozoa.

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Electroejaculation and semen characteristics of Asiatic Black bears (Ursus thibetanus)

Cited by 20 publications

References 13 publications

Sperm Cryopreservation in Brown Bear (Ursus arctos): Preliminary Aspects

Sperm Cryopreservation in Brown Bear (Ursus arctos): Preliminary Aspects

Salvaging urospermic ejaculates from brown bear (Ursus arctos)

Effects on brown bear (Ursus arctos) spermatozoa freezability of different extender and dilution ratios used for pre-freezing centrifugation

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