Cryopreservation of rooster sperm

Area of Science:

• Animal Science
• Reproductive Biology
• Cryobiology

Background:

• Successful sperm cryopreservation requires optimal diluent, cryoprotectant, freezing/thawing rates, and removal of deleterious substances.
• Economical cryopreservation necessitates sperm recovery with sufficient fertilization capacity for maximum utilization of superior males.

Purpose of the Study:

• To evaluate a novel semen freezing container (BioPore CryoCell container) for reproducible cryopreservation and glycerol removal.
• To determine the effects of residual glycerol, initial glycerol concentration, buffer type, and dialysis time on sperm fertility after cryopreservation.

Main Methods:

• Experiments involved freezing and thawing rooster sperm in CryoCell containers at 6°C/min.
• The study assessed the impact of varying residual glycerol levels, initial glycerol concentrations (8%, 10%, 12%), buffer types (Beltsville Poultry Semen Extender, Minnesota A), and dialysis times (60, 90, 120 min).
• Fertility was evaluated through intravaginal insemination of hens with cryopreserved and thawed sperm.

Main Results:

• 0.8% (vol/vol) residual glycerol reduced fertility by 5-10%.
• 12% initial glycerol concentration was superior to 10% and 8%.
• No significant difference was observed between the two buffers; 90 and 120 min dialysis times were superior to 60 min.
• Cryopreservation using CryoCell containers and 90-120 min dialysis yielded a mean fertility of 55.6% in over 3,000 eggs from 400 hens.

Conclusions:

• The novel BioPore CryoCell container facilitates reproducible sperm cryopreservation and efficient glycerol removal.
• An optimized protocol involving 12% glycerol, 90-120 min dialysis, and the CryoCell container consistently achieves over 50% fertility.
• This cryopreservation method is amenable to scale-up for commercial applications in poultry breeding.