1a. Objectives (from AD-416):
The long-term goal of this research team is to develop efficient methods of preserving poultry, swine and fish germplasm. Over the next five years we will (1) identify the physiological and biochemical impacts of hypothermic storage on poultry, swine and fish sperm, (2) elucidate the cellular and molecular mechanisms controlling sperm selection, transport and storage in the female reproductive tract of poultry, (3) determine the impact of genetics on the success of semen storage methodology for poultry and swine, and (4) investigate alternative strategies for conserving valuable poultry and swine germplasm. Alternative strategies to be investigated include: 1) creation of transient pores and/or use of endogenous plasma membrane transporters to deliver antioxidants, cryoprotectants and/or nutrients intracellularly; 2) development of diets to modify the plasma membranes of sperm from congenic and/or inbred poultry lines to improve cryosurvival; and 3) development of methods to isolate, propagate, freeze/thaw and transfer poultry spermatogonia to recipient sterilized testes.
1b. Approach (from AD-416):
In the food animal industries, production of offspring that possess economically important traits is most effectively accomplished by artificial insemination (AI) or in vitro fertilization (IVF), where semen from a few males is distributed among a large number of females. The poultry and swine industries use AI in their breeding programs to accelerate genetic advancement, while the striped bass industry relies on IVF. Because of gaps in our fundamental knowledge of sperm biology, the fate of sperm in the oviduct and impact of freezing on sperm function, there has been limited success in the long-term preservation of poultry, swine and bass germplasm, and existing methodologies are not adequate for the needs of these industries. Development of effective semen storage methodology necessitates a scientific foundation addressing the cellular and molecular biology of both the sperm cell and the female cells that interact with sperm after insemination. Experiments in this project will address these fundamental questions by focusing on (1) sperm membrane composition and energetics before and after hypothermic storage, (2) impact of sperm on oviductal epithelial cell gene expression and secretory activity, and (3) potential genetic basis of sperm cryosurvival. Included in this project are several alternative strategies for germplasm preservation: introduction of cryoprotectants intracellularly; dietary modification of sperm cell membranes; and use of cryopreserved testicular cells as an alternative means of male germplasm cryopreservation. This systematic approach will address the gaps in our knowledge and permit development of novel and/or more efficient methods of preserving poultry, swine and fish semen.
3. Progress Report:
This is a bridge project of 1265-31000-093-00D/411596. Progress can be found on the new project 1245-31000-105-00D.