Application of Cryopreservation of Chicken Semen for Biodiversity
Theme: Sperm cryopreservation used to restore endangered breeds or species of chicken which involve male selection and management, semen collection, and freezing duration, cryoprotective agent (CPA), equilibrium time between sperm and CPA, semen packaging, freezing method, freezing rate of sperm as well as thawing rate, removal of glycerol diluent, female management for insemination, different types of insemination method for successful fertilization.
Introduction: Cryopreservation is used to preserve the genetic resources and diversity achieved by methods of storage of cells showing species-dependent reproductive potential. They mainly include the cryopreservation of sperm, embryos, gonadal tissue, and in specific species, primordial germ cells (FAO, 2021). Cryopreservation involves the collection of large amounts of cells for long–term storage, long-distance genetic exchange, and genetic resources management.
Subject matter: Cryopreservation carries out as follows:
1. Collection: Semen will be collected from a male of 30-40 weeks, by dorso-abdominal massage in a container. It should be free of faces, urates, and transparent fluids which ultimately affect the quality of sperm. Semen will be tested further for sperm motility, viability, and membrane fluidity. There should be a short duration between collection and freezing.
2. Preparation: We add intracellular and extracellular diluents such as glycerol, dimethyl sulphoxide, dimethyl acetamide and raffinose, trehalose, sucrose, and polyethylene respectively for regulating the formation of ice crystals which are extensively important for cryopreservation at 2-4°C equilibrium between sperm and diluents.
3. Freezing: Semen may be packaged in glass ampoules, plastic straws, and pellets but plastic straws are preferred for handling, storing capacity, biosecurity, and precise identification of individual animals. The semen freezing rate for dimethyl formamide/plastic straw and ethylene glycol/plastic straws are -15 and -1oC/min respectively for maintaining quality and reducing sperm metabolism, function, and proteolytic activities.
4. Thawing: Semen will be thawed at 5oC or 60oC with glycerol or dimethyl acetamide leading to desirable quality by maintaining growing crystals.
5. AI: The frozen/thawed chicken semen is inseminated through intravaginal, intrauterine, intravaginal, and intraperitoneal inseminations into the lay.
Conclusion: An essential strategy used to protect the genetic resources and biodiversity of endangered breeds or species.