Cryopreservation of Plagiognathops microlepis sperm

Area of Science:

• Aquaculture and Reproductive Biology
• Cryobiology and Gamete Preservation
• Fish Breeding and Genetics

Background:

• Sperm cryopreservation is crucial for genetic resource management in fish aquaculture.
• Optimizing cryopreservation protocols is essential to maintain sperm viability and fertilization capacity post-thaw.

Purpose of the Study:

• To determine the optimal conditions for cryopreserving male fish sperm.
• To evaluate the effects of different extenders, cryoprotectants, dilution ratios, and cooling/thawing parameters.

Main Methods:

• Sperm was cryopreserved in 0.25 ml straws using various extenders, cryoprotectants (including DMSO), dilution ratios, equilibration times, cooling heights, and thawing temperatures.
• A two-step cooling protocol and a programmed cooling protocol were evaluated.
• Motility and fertilization rates were assessed post-thaw.

Main Results:

• The optimal protocol involved a 1:7 dilution in D-16 with 5% DMSO, 20 min equilibration, cooling to 3 cm above liquid nitrogen for 10 min, and thawing at 40°C.
• This resulted in post-thaw motility of 35.33% and fertilization rates of 39.00%.
• A programmed cooling protocol yielded a post-thaw activation rate of 36.67%.

Conclusions:

• The established cryopreservation protocol provides moderate success but requires further optimization.
• Achieving higher post-thaw motility and fertilization rates is necessary for effective application in fish breeding programs.