The advantages of combining low-density lipoproteins with glutamine for cryopreservation of canine semen.
Twenty sperm samples from five dogs were frozen in liquid nitrogen at -196 degrees C in 16 different media, two control media containing 20% egg yolk and 6% low-density lipoproteins (LDL); 10 test media containing 6% LDL (the active cryoprotective ingredient of chicken egg yolk) combined with 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mmol of glutamine respectively at 4%, 5%, 7%, and 8% LDL. Following thawing, sperm mobility was assessed using an image analyser, HAMILTON THORN CERROS 12. The percentage of mobile spermatozoa was 62.05% in the 6% LDL + 20 mmol glutamine medium compared with 48.90% in the egg yolk-based medium (p < 0.05) or 57.55% for the 6% LDL medium (p < 0.05). Furthermore, in most cases, the motility parameters (average path velocity, curvilinear velocity, straight line velocity) in the 6% LDL + 20 mmol glutamine medium, were superior, to a statistically significant extent, to those in the control media. Finally, the 6% LDL + 20 mmol glutamine combination provides spermatozoa with better protection during freezing than egg yolk or the 6% LDL medium alone in terms of acrosome integrity (fluorescein isothiocyanate--Pisum sativum agglutinin test: p < 0.05), the flagellar plasma membrane (hypo-osmotic test: p < 0.05 for 6% LDL), the DNA (acridine orange test; no significant difference) and the integrity of the acrosome (Spermac test: no significant difference).
Bencharif
D
D
Laboratory of Biotechnology and Pathology of Reproduction, National Veterinary School of Nantes, Nantes, France. bencharif@vet-nantes.fr
Amirat
L
L
Pascal
O
O
Anton
M
M
Schmitt
E
E
Desherces
S
S
Delhomme
G
G
Langlois
M-L
ML
Barrière
P
P
Larrat
M
M
Tainturier
D
D
D000818:Animals; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000494:pharmacology; D004285:Dogs / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005973:Glutamine / Q000494:pharmacology*; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D008297:Male; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects / Q000502:physiology
D003451:Cryoprotective Agents; D008077:Lipoproteins, LDL; D005973:Glutamine