Evaluation of meiotic progression of bovine oocytes supplemented with oviduto glycoprotein 1 (OVGP1) during the four and six final hours of in vitro maturation

• Grant number: 20/09778-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2020
• End date: August 31, 2021
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Sheila Merlo Garcia Firetti
• Grantee: Jaqueline Aparecida Andrelo de Lima
• Host Institution: Faculdade de Ciências Agrárias. Universidade do Oeste Paulista (UNOESTE). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

The development of alternatives to optimize the productivity of the herd is the current challenge for researchers. In vitro embryo production emerges as a main tool that needs viable and quality gametes to be successful. Therefore, this proposal aims to study the quality of in vitro maturation of oocytes with different times of supplementation with glycoprotein 1 of oviduct (OVGP1), through nuclear progression, of oocytes from ovaries of female slaughterhouses, and determine the time supplementation that will indicate greater viability for the in vitro maturation procedure. Supplementation times for oocyte maturation in vitro will be tested according to the following treatment: Treatment 1 (control 1) = maturation medium with SFB (fetal bovine serum) without OVGP1, Treatment 2 (control 2) = maturation with BSA (bovine serum albumin) without OVGP1, Treatment 3 = maturation medium with BSA + OVGP1 supplemented in the final 4 hours of IVM and Treatment 4 = maturation medium with BSA + OVGP1 supplemented in the final 6 hours of IVM. The follicles will be aspirated and the oocytes selected in Grade I and II. Five repetitions will be performed, with (n = 75) oocytes recovered for each repetition, with 15 oocytes being evaluated before maturation and the others will be submitted to maturation in vitro according to the experimental groups, totaling 60 oocytes matured by repetition. For analysis of nuclear progression, the oocytes will be stained with HOECHST (33342, Sigma Co., St. Louis, USA) and individually evaluated under an epifluorescence microscope. The data will be subjected to the Shapiro-Wilk normality test analyzed using the ANOVA test followed by the Tukey or Chi-square test (X²) at a significance level of 5% according to the normality results, using the Statistical Analysis System program for Windows (SAS Inst., Inc., Cary, NC). With this research, it is expected to obtain important results that will aggregate the knowledge of the present study area and optimization of the PIVE technique. (AU)