FOLLICLE SYNCHRONIZATION AND OOCYTE MATURATION IN MARES: USE OF PHYSIOLOGICAL PARAMETERS TO ENHANCE IN VITRO EMBRYO PRODUCTION

• Grant number: 23/07531-3
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2024
• End date: March 31, 2026
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: José Buratini Junior
• Grantee: José Buratini Junior
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The mechanisms involved in the induction of mare ovulation need to be better elucidated, since the physiology of follicular development and ovulation in mares presents differences compared to other domestic species. In vitro oocyte maturation (IVM) is widely studied in several mammals, including horses, due to its importance within in vitro embryo production (IVP) protocols. Immature oocytes submitted to IVM come from follicles at different stages of development and, therefore, are heterogeneous in terms of the degree of chromatin condensation and stores of important transcripts for early embryonic development. The proposed project aims to characterize the oocyte population in terms of chromatin configuration at the time they are aspirated from donors and to validate a strategy for obtaining homogeneous oocytes. In parallel, this project aims to develop a sequential culture system adjusted to the maturation stage of oocytes recovered from donor mares. The experiments included in this step aim to test the doses of peptides present in the mare's reproductive physiology and establish the fundamentals of sequential cultivation, in order to mimic intrafollicular conditions before (pre-IVM phase) and during ovulation (MIV phase). This strategy may allow in vitro cultivation of a known homogeneous population, with physiological agents adapted to the phase they are in, which may improve maturation and fertilization rates and embryonic development. (AU)