title: Effects on the quality of frozen-thawed alpaca (Lama pacos) semen using two different cryoprotectants and extenders.
abstract: OBJECTIVE
  To evaluate two extenders and two cryoprotectant agents (CPA) for alpaca semen cryopreservation.
  
  
  METHODS
  Semen samples were obtained from four adult alpacas (Lama pacos) and frozen using extender I (TRIS, citrate, egg yolk and glucose) or extender II (skim milk, egg yolk and fructose), each containing either glycerol (G) or ethylene glycol (EG) as CPA. Consequently, four groups were formed: 1) extender I-G; 2) extender I-EG; 3) extender II-G; and 4) extender II-EG. Semen was diluted in a two-step process: for cooling to 5 degrees (extenders without CPA), and for freezing (extenders with CPA). Viability and acrosome integrity were assessed using trypan blue and Giemsa stains.
  
  
  RESULTS
  When compared, the motility after thawing was higher (P >0.05) in groups II-EG (20.0% +/- 6.7%) and II-G (15.3 % +/- 4.1% ) than that in groups I-G (4.0 % +/- 1.1%) and I-EG (1.0 % +/- 1.4%). Viable spermatozoa with intact acrosomes in groups II-EG (18.7 % +/- 2.9%) and II-G (12.7 % +/- 5.9%) were higher than that in groups I-G (5.7% +/- 1.5%) and I-EG (4.0% +/- 1.0%).
  
  
  CONCLUSIONS
  The skim milk- and egg yolk-based extenders containing ethylene glycol or glycerol to freeze alpaca semen seems to promote the survival of more sperm cells with intact acrosomes than the other extenders.
authors.affiliation: Veterinary Institute for Tropical and Highland Research, Faculty of Veterinary Medicine, Universidad Nacional Mayor de San Marcos, P.O. Box 03-5034, Lima 41, Perú.
authors.forename: Alexei
authors.initials: A
authors.lastname: Santiani
authors.forename: Wilfredo
authors.initials: W
authors.lastname: Huanca
authors.forename: Rómúlo
authors.initials: R
authors.lastname: Sapana
authors.forename: Teodosio
authors.initials: T
authors.lastname: Huanca
authors.forename: Néstor
authors.initials: N
authors.lastname: Sepúlveda
authors.forename: Raúl
authors.initials: R
authors.lastname: Sánchez
mesh_terms: D000818:Animals; D002161:Camelids, New World; D003451:Cryoprotective Agents / Q000008:administration & dosage; D005615:Freezing; D008297:Male; D012661:Semen; D012662:Semen Preservation; D013081:Sperm Motility
chemical_list: D003451:Cryoprotective Agents