title: Does the inclusion of protease inhibitors in the insemination extender affect rabbit reproductive performance?
abstract: The bioavailability of buserelin acetate when added to the seminal dose appears to be determined by the activity of the existing aminopeptidases. Thus, the addition of aminopeptidase inhibitors to rabbit semen extenders could be a solution to decrease the hormone degradation. This study was conducted to evaluate the effect of the protease activity inhibition on rabbit semen quality parameters and reproductive performance after artificial insemination. Seminal quality was not affected by the incubation with protease inhibitors, being the values of motility, viability, and acrosome integrity not significantly different between the protease inhibitors and the control group. In addition, seminal plasma aminopeptidase activity was inhibited in a 55.1% by the protease inhibitors. On the other hand, regarding the effect of protease inhibitors on reproductive performance, our results showed that the presence of protease inhibitors affected the prolificacy rate (9.2 ± 0.26 and 9.3 ± 0.23 vs. 8.2 ± 0.22 total born per litter for negative control, positive control, and aminopeptidase inhibitors group, respectively; P < 0.05), having this group one kit less per delivery. We conclude that the addition of a wide variety of protease inhibitors in the rabbit semen extender negatively affects prolificacy rate. Therefore, the development of new extenders with specific aminopeptidase inhibitors would be one of the strategies to increase the bioavailability of GnRH analogues without affecting the litter size.
authors.affiliation: Centro de Investigación y Tecnología Animal-Instituto Valenciano de Investigaciones Agrarias (CITA-IVIA), Castellón, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Casares-Crespo
authors.affiliation: Instituto de Ciencia y Tecnología Animal, Universidad Politécnica de Valencia, Valencia, Spain.
authors.forename: J S
authors.initials: JS
authors.lastname: Vicente
authors.affiliation: Instituto de Ciencia y Tecnología Animal, Universidad Politécnica de Valencia, Valencia, Spain.
authors.forename: A M
authors.initials: AM
authors.lastname: Talaván
authors.affiliation: Centro de Investigación y Tecnología Animal-Instituto Valenciano de Investigaciones Agrarias (CITA-IVIA), Castellón, Spain. Electronic address: viudes_mar@gva.es.
authors.forename: M P
authors.initials: MP
authors.lastname: Viudes-de-Castro
mesh_terms: D000818:Animals; D002064:Buserelin / Q000494:pharmacology; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000494:pharmacology*; D005260:Female; D005298:Fertility / Q000187:drug effects; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary; D008098:Litter Size / Q000187:drug effects; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D011480:Protease Inhibitors / Q000494:pharmacology*; D011817:Rabbits; D012098:Reproduction / Q000187:drug effects*; D055101:Semen Analysis / Q000379:methods / Q000662:veterinary; D012662:Semen Preservation / Q000379:methods* / Q000662:veterinary; D013081:Sperm Motility / Q000187:drug effects
chemical_list: D003451:Cryoprotective Agents; D011480:Protease Inhibitors; D002064:Buserelin
keywords: Aminopeptidase activity; Protease inhibitor; Rabbit; Reproductive performance; Seminal quality