Over 92 species of reptiles, amphibians, birds, and mammals have developed the ability to store ejaculated sperm in the female reproductive tract for extended periods of time (days to years) with no decrease in its ability to fertilize the ovum. However, in most mammals sperm can be maintained for up to 15 days in the cauda epididymis, but only live for approximately 24 hours after ejaculation. The long term goal of this research is to determine the mechanisms by which sperm can be stored long term in the female reproductive tract of chickens and in the epididymis of the bull, and to utilize the knowledge to develop a cold-chain-free system to allow artificial insemination of domestic farms animals, especially in developing countries that do not have the infrastructure for cryopreservation. A thorough understanding of the proteins that create the microenvironment of the epididymis and chicken semen storage tubules will advance our understanding of how these proteins may enhance membrane integrity to improve long term storage. Leveraging the new knowledge of the epididymal environment should enable cold-free sperm storage for extended periods, and may have other applications for somatic cell preservation.
Studies supported by this award will utilize 2D LC-MS/MS to compare protein profiles of bovine epididymal sperm and ejaculated sperm to the protein profiles of chicken sperm stored in the female reproductive tract, and determine the mitochondrial activity in each group of sperm. To determine if increased longevity is accomplished through decreased activity. Ejaculated bull sperm will then be washed and cultured in media containing epididymal or chicken proteins at the pH of epididymal sperm to determine changes in sperm kinetics. The PI will recruit one Master's student to be an integral part of this proposal, and will continue to recruit undergraduate students and international interns for research training and direct involvement in the research efforts. Results from the study will be published in peer-reviewed journals and disseminated through scientific conferences.
