Research Project: Development of New Technologies and Methods to Enhance the Fertility, Utilization, and Long-Term Storage of Poultry and Swine Germplasm

Location: Animal Biosciences & Biotechnology Laboratory

Project Number: 8042-31000-110-000-D
Project Type: In-House Appropriated

Start Date: Aug 13, 2018
End Date: Aug 11, 2022

Objective:
Objective 1: Identify genetic markers and semen biological markers that can effectively predict fertility traits in poultry and swine. • Sub-objective 1.A. Discover biomarkers associated with the high and low sperm mobility phenotypes in adult male poultry. • Sub-objective 1.B. Delineate genetic markers associated with the high and low sperm mobility phenotypes in poultry and use to predict the phenotype of sexually immature males. • Sub-objective 1.C. Identify biological and/or functional parameters associated with fertility in boars. • Sub-objective 1.D. Elucidate genetic markers associated with high and low fertility in boars. Objective 2: Determine the contribution of genetics and other factors towards the survival and fertility of frozen/thawed semen in poultry. • Sub-objective 2.A. Develop a turkey line with superior sperm function by selecting for the duration of fertility of frozen/thawed semen. • Sub-objective 2.B. Characterize sperm function and protein expression of males from superior cryosurvival lines and compare with unselected lines. • Sub-objective 2.C. Identify molecular and cellular mechanisms associated with early embryonic mortality in turkey embryos originating from insemination with frozen/thawed semen. Objective 3: Delineate the molecular and physiological mechanisms associated with in vivo sperm storage and duration of fertility in poultry. • Sub-objective 3.A. Characterize gene expression of sperm storage tubules from virgin, high-fertility and low-fertility hens and identify genetic markers associated with duration of fertility. • Sub-objective 3.B. Identify biological pathways associated with the function of sperm storage tubules. Objective 4: Develop ovarian cryoconservation for the turkey to fully capture the female genetic contribution and augment germplasm cryopreservation efforts. • Sub-objective 4.A. Characterize the ovarian morphology of young female poults and determine the optimal age for ovary vitrification. • Sub-objective 4.B. Identify the optimal recipient age and develop an immunosuppressant protocol to prevent rejection of donor tissue. • Sub-objective 4.C. Use optimized methods to recreate a unique research line from vitrified ovaries.

Approach:
The long-term goals of this Project Plan are to improve the efficiency of reproduction and germplasm preservation in swine and poultry to meet the demands of feeding a growing human population. Reproductive traits exhibit low heritability and phenotypically cannot be measured prior to sexual maturity. Moreover, the ability to recover poultry lines from frozen/thawed semen continues to be unreliable. Central focus areas of this Project Plan are to provide the swine and/or poultry industries with the knowledge and tools to (1) predict male fertility, (2) store semen under hypothermic conditions without a substantial loss in fertility, and (3) preserve the female genetic contribution for complete line regeneration. To enable prediction of male fertility, males with known fertility will be evaluated for genetic and biological markers associated with the sperm mobility phenotype and the sperm zinc signature. Several approaches will be used to improve hypothermic semen storage, including: 1) development of a cryoresistant turkey line (e.g. selected for superior sperm cryosurvival) to elucidate biological attributes associated with superior sperm cryosurvival; 2) an investigation of why there is such a high incidence of early embryonic death when frozen/thawed turkey semen is used for insemination; and 3) identifying biological pathways associated with sperm storage tubules in the hen to better mimic the in vivo semen storage environment and improve in vitro storage conditions. Finally, cryopreserved semen alone is not adequate for complete line regeneration in birds because the female gamete determines gender and the biology of the avian egg prevents traditional cryopreservation of this gamete. Transplanting frozen/thawed immature ovarian tissue will be investigated as a means to preserve female germplasm for the turkey. All these approaches will contribute to improving reproductive efficiency.