title: Comparison of two dilution rates on canine semen quality after cryopreservation in a coconut water extender.
abstract: The objective of the present study was to evaluate the effect of sperm dilution (one part semen:one part extender or at 200 x 10(6) spermatozoa/mL) using a coconut water extender on the post-thaw sperm quality. Twelve ejaculates were collected from six dogs. Semen was divided into two aliquots, one for dilution one part semen:one part extender (group 1) and another for a concentration of 200 x 10(6) spermatozoa/mL (group 2). Semen was initially extended at 37 degrees C at a proportion of one part semen:half part extender (1:1/2) for group 1 (A-fraction). For group 2, the volume for a concentration of 200 x 10(6) spermatozoa/mL was calculated and a half of this volume was used for the initial dilution (A-fraction, 37 degrees C). Coconut water extender containing 20% egg yolk was used for this initial dilution in both groups. After dilution, the semen was cooled for 40 min in a thermal box (15 degrees C) and for 30 min in a refrigerator. The other half of the extender (B-fraction) containing egg yolk and glycerol (12%) was added to semen in both groups. Subsequently, the final concentration of glycerol in the extender was 6%. Ejaculates were frozen in 0.25 mL straws 5 cm above the surface of liquid nitrogen and stored at -196 degrees C. After 1 week, straws were thawed at 37 degrees C for 1 min and the microscopic criteria were evaluated. The dilution method had no influence on sperm motility, vigor and normal spermatozoa (71.4 compared with 67.7%). There was no effect of dog, ejaculate within male on post-thaw semen quality. Moreover, there was not a male x treatment interaction. Both treatments were efficient in preserving sperm quality.
authors: Laboratory of Carnivore Reproduction, State University of Ceará, Paranjana 1700, 60740000 Itaperi, Fortaleza, Ceará, Brazil. cardosorcs@yahoo.com.br
authors: Rita
authors: R
authors: de Cássia Soares Cardoso
authors: Alexandre Rodrigues
authors: AR
authors: Silva
authors: Lúcia Daniel Machado
authors: LD
authors: da Silva
mesh_terms: D000818:Animals; D003059:Cocos / Q000737:chemistry; D015925:Cryopreservation / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004285:Dogs / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D012661:Semen / Q000166:cytology; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013076:Sperm Count / Q000592:standards / Q000662:veterinary*; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000502:physiology*
chemical_list: D003451:Cryoprotective Agents