title: Comparison of four different permitting and combination of two best cryoprotectants on freezing Nguni sperm evaluated with the aid of computer aided sperm analysis.
abstract: Cryopreservation has been reported to damage approximately 40-50% of viable sperm in bull semen. The present study was undertaken to assess the cryo-effectiveness of glycerol (GLY), ethylene glycol (EG), dimethyl sulfoxide (DMSO) and propylene glycol (PND) as cryoprotectant during the cryopreservation of Nguni bull semen. Semen was collected from 18 Nguni bulls and evaluated macroscopically and microscopically for sperm parameters. Thereafter, the semen samples were diluted with egg-yolk citrate extender supplemented with either 12% GLY or DMSO or EG or PND cryoprotectant. Semen samples were loaded into straws and placed into a controlled rate programmable freezer and stored in a liquid nitrogen tank. Following semen thawing, artificial insemination (AI) was done on synchronized Nguni cows. The in vitro fertilization (IVF) was conducted on cow's oocytes to test the fertilizing ability. Data was analyzed with the aid of ANOVA. A significant difference (p < 0.05) was recorded between fresh total sperm motility rate (94.7 ± 2.6%) and frozen-thawed sperm total motility rate with GLY (77.8 ± 11.0%), EG (20.4 ± 10.1%), DMSO (15.7 ± 11.9%) and PND (11.2 ± 11.3%). Interestingly, a positive correlation between total sperm motility and pregnancy rate (r = 0.42) was recorded. However, a negative correlation of Nguni sperm parameters with IVF (r = -0.53) was obtained. The freezing-thawing process did reduce the Nguni sperm total sperm motility percentage.
authors.affiliation: Agricultural Research Council, Animal Production Institute, Germplasm Conservation and Reproductive Biotechnologies, Private Bag X2, Irene 0062, South Africa; Tshwane University of Technology, Faculty of Science, Department of Animal Sciences, Private Bag X 680, Pretoria 0001, South Africa; Department of Agriculture, Land Reform & Development, Vaalharts Research Station, Private Bag X9, Jan Kempdorp 8550, South Africa.
authors.forename: Mokgadi Magdelin
authors.initials: MM
authors.lastname: Seshoka
authors.affiliation: Agricultural Research Council, Animal Production Institute, Germplasm Conservation and Reproductive Biotechnologies, Private Bag X2, Irene 0062, South Africa; University of the Free State, Wildlife and Grassland Sciences, Department of Animal, P.O Box 339, Bloemfontein 9300, South Africa. Electronic address: masindim@arc.agric.za.
authors.forename: Masindi L
authors.initials: ML
authors.lastname: Mphaphathi
authors.affiliation: Agricultural Research Council, Animal Production Institute, Germplasm Conservation and Reproductive Biotechnologies, Private Bag X2, Irene 0062, South Africa; Tshwane University of Technology, Faculty of Science, Department of Animal Sciences, Private Bag X 680, Pretoria 0001, South Africa; University of the Free State, Wildlife and Grassland Sciences, Department of Animal, P.O Box 339, Bloemfontein 9300, South Africa. Electronic address: NedambaleTL@tut.ac.za.
authors.forename: Tshimangadzo L
authors.initials: TL
authors.lastname: Nedambale
mesh_terms: D000818:Animals; D002417:Cattle; D015925:Cryopreservation / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004530:Egg Yolk; D019855:Ethylene Glycol / Q000494:pharmacology; D005307:Fertilization in Vitro / Q000662:veterinary*; D005615:Freezing; D005990:Glycerol / Q000494:pharmacology; D007315:Insemination, Artificial / Q000662:veterinary*; D008297:Male; D019946:Propylene Glycol / Q000494:pharmacology; D055101:Semen Analysis; D012662:Semen Preservation / Q000662:veterinary*; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects
chemical_list: D003451:Cryoprotective Agents; D019946:Propylene Glycol; D019855:Ethylene Glycol; D005990:Glycerol; D004121:Dimethyl Sulfoxide
keywords: CASA; Cryoprotectants; IVF; Nguni bull semen; Pregnancy rate