Successful fertilization of Varicorhinus macrolepis eggs with sperm subjected to two freeze-thaw cycles

Theriogenology. 2008 Apr 15;69(7):793-7. doi: 10.1016/j.theriogenology.2007.10.022. Epub 2008 Mar 11.

Abstract

Although sperm from several fish species have been successfully cryopreserved, few studies have been done in small and/or endangered species. The aim of the present work was to develop a method of freezing and refreezing Varicorhinus macrolepis semen in 1.8 mL cryovials. The effect of extenders and cryoprotectants on the motility of post-thaw sperm was examined. The motility of frozen-thawed sperm in extender D-15 was higher than that in MPRS and fish Ringer solution (P<0.05). Dimethyl sulfoxide (DMSO) and glycerol provided greater protection to sperm than methanol during freezing and thawing; the most effective concentration of DMSO and glycerol was 10%. The fertilization rate of frozen-thawed sperm was not significantly different from that of fresh sperm. Furthermore, mean (+/-S.D.) hatching rate did not differ significantly between frozen-thawed (82.7+/-12.4%) and fresh sperm (90.7+/-4.5%). Although frozen-thawed sperm that was immediately refrozen had 0% post-thaw motility, frozen semen that was refrozen after dilution with D-15 (containing DMSO at a ratio of 1:2) had post-thaw motility of 38.3+/-2.9%. Motility was lower for refrozen than for frozen sperm (P<0.05). Furthermore, fertilization and hatching rates of refrozen sperm were 42.9+/-6.7 and 34.1+/-10.5%, respectively, which were lower than that of fresh sperm (P<0.05).

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cryopreservation*
  • Cryoprotective Agents / pharmacology
  • Cyprinidae / physiology*
  • Eggs*
  • Female
  • Fertilization / drug effects
  • Fertilization / physiology*
  • Freezing
  • Male
  • Semen Preservation / adverse effects
  • Sperm Motility / drug effects
  • Spermatozoa / cytology
  • Spermatozoa / physiology*

Substances

  • Cryoprotective Agents