Cryopreservation and post-thawed fertility of ram semen frozen in different trehalose concentrations.
We evaluated freeze-thawing tolerance of heterospermic ram spermatozoa (Pampinta breed) in a base diluent (Tris, citric acid, fructose, egg yolk, glycerol) with the addition of different trehalose concentrations (0-400 mOsm). We chose sperm motility, acrosome integrity and hypo-osmotic swelling test as parameters to evaluate cryopreservation capacity. We obtained the best results for 50 and 100 mOsm trehalose-supplemented extenders, with values (referred to fresh semen values) of 65% for motility, 75% for acrosome integrity and 50% for hypo-osmotic swelling test, while freeze-thawing tolerance diminished significantly for 200 and 400 mOsm of the disaccharide. Fertility values measured at lambing were 47.1 and 44.6% (2 consecutive years), using semen cryopreserved in 100 mOsm trehalose-containing diluent, which is 2.5 times greater than those obtained with the base diluent (18.5 and 14.5%). We conclude that the membrane-protecting disaccharide trehalose confers a greater cryoprotective capacity to the base extender, when added up to 100 mOsm. This action is reflected in the different sperm membranes, the motile activity and in vivo fertility.
Aisen
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EG
Laboratorio de Teriogenología, Facultad de Ciencias Agrarias, Universidad Nacional del Comahue, Río Negro, Argentina. eduardoaisen@hotmail.com
Medina
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VH
Venturino
A
A
D000177:Acrosome / Q000648:ultrastructure; D000818:Animals; D048429:Cell Size; D002951:Citrates; D015925:Cryopreservation / Q000662:veterinary*; D005260:Female; D005298:Fertility; D006358:Hot Temperature; D007038:Hypotonic Solutions; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D009994:Osmolar Concentration; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D012756:Sheep; D000077559:Sodium Citrate; D013081:Sperm Motility; D013094:Spermatozoa / Q000648:ultrastructure; D014199:Trehalose / Q000008:administration & dosage*
D002951:Citrates; D007038:Hypotonic Solutions; D000077559:Sodium Citrate; D014199:Trehalose