title: Milt cryopreservation for rheophilic fish threatened by extinction in the Rio Grande, Brazil.
abstract: BACKGROUND
  Specific protocols for milt cryopreservation have been established for some freshwater fish species. However, cryopreservation reduces sperm quality, giving unsatisfactory results in reproduction.
  
  
  OBJECTIVE
  The objective of this work was to evaluate the effect of different cryoprotectants on the quality of Prochilodus lineatus, Brycon orbignyanus and Piaractus mesopotamicus milt after cryopreservation.
  
  
  METHODS
  The milt was diluted in different cryoprotectant solutions containing 10% methanol, dimethyl sulfoxide, glycerol, propylene glycol or ethylene glycol combined with the Beltsville Thawing Solution extender (5%), then placed in the vapour of a liquid nitrogen (LN) storage tank for 24 h, after which they were immersed in LN. After rewarming, the rate (%) and duration (s) of milt motility and abnormal morphology were evaluated.
  
  
  RESULTS
  All of cryoprotectant solutions tested used maintained the viability of P. lineatus and P. mesopotamicus milt. However, in P. lineatus, glycerol ensured a lower percentage of abnormal morphology. In case of P. mesopotamicus, all of the cryoprotectant solutions tested may be used in the cryopreservation process, with the exception of those containing glycerol.
  
  
  CONCLUSIONS
  For B. orbignyanus, cryoprotectant solutions containing methanol and ethylene glycol are recommended for use in the cryopreservation process, although they reduced the quality of sperm post-rewarming.
authors.forename: Estefânia Souza
authors.initials: ES
authors.lastname: de Andrade
authors.forename: Daniella Aparecida de Jesus
authors.initials: DA
authors.lastname: Paula
authors.forename: Viviane de Oliveira
authors.initials: Vde O
authors.lastname: Felizardo
authors.forename: Luis David Solis
authors.initials: LD
authors.lastname: Murgas
authors.forename: Galileu Crovatto
authors.initials: GC
authors.lastname: Veras
authors.forename: Priscila
authors.initials: P
authors.lastname: Vieira e Rosa
mesh_terms: D000818:Animals; D001938:Brazil; D002470:Cell Survival / Q000187:drug effects; D003247:Conservation of Natural Resources; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D019855:Ethylene Glycol / Q000494:pharmacology; D005399:Fishes / Q000502:physiology*; D005990:Glycerol / Q000494:pharmacology; D008297:Male; D000432:Methanol / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D011108:Polymers / Q000494:pharmacology; D011409:Propylene Glycols / Q000494:pharmacology; D012662:Semen Preservation / Q000379:methods*; D013076:Sperm Count; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
chemical_list: D003451:Cryoprotective Agents; D011108:Polymers; D011409:Propylene Glycols; C012504:polypropylene glycol; D019855:Ethylene Glycol; D005990:Glycerol; D000432:Methanol; D004121:Dimethyl Sulfoxide