Relationship between sperm subpopulations in Senepol bulls with in vitro embryo production

Author(s)

Suzane Peres Campanholi

• Document type: Doctoral Thesis
• Press: Jaboticabal. 2020-06-08.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2019-11-08
• Advisor: Lindsay Unno Gimenes; Fabio Morato Monteiro

Abstract

In cattle, in vitro embryo production (IVEP) is one of the most important reproductive biotechnologies in Brazil, being responsible for the rapid expansion of the Senepol breed in our country. Estimating IVEP in Senepol animals based on seminal analysis of breeders would be valuable for the semen cryopreservation industry, research institutes and Senepol cattle breeders. Spermatozoa that differ in their motility pattern coexist in an ejaculate and can be grouped into different sperm subpopulations after kinetic analysis with the CASA system (Computer-assisted sperm analysis). Combining this assessment with other analyzes of sperm quality and analyzing the results with multivariate statistics and artificial intelligence can help to improve a breeder's fertility estimate. Therefore, the objectives in the present study were: 1) identify and characterize sperm subpopulations in cryopreserved semen of Senepol bulls after washing process for in vitro fertilization (IVF); 2) generate a statistical model to estimate IVEP based on the sperm subpopulations and other sperm attributes analyzed, using multivariate statistical analysis and 3) apply artificial intelligence, through the use of artificial neural networks (ANNs) in order to improve the estimate of IVEP. Retrospective data from 386 IVEP routines were obtained from the records belonging to the enterprise In Vitro Brasil and embryonic production was categorized as high, medium and low. After, 38 samples of cryopreserved semen from Senepol bulls, used in IVEP routines, were acquired from the enterprise Senepol 3G for evaluation. After thawed, all samples were evaluated for sperm morphology and then subjected to a washing process that is performed before IVF. After washing, all samples were evaluated by the CASA system to obtain the general kinetics of the samples and the individual kinetics of the sperm. In addition, flow cytometry was evaluated for the integrity of the plasma and acrosomal membranes, mitochondrial potential, oxidative status and chromatin resistance. After multivariate analyzes of principal components and grouping, three sperm subpopulations were identified: SBP1 (fast and progressive motility), SBP2 (hyperactived motility) and SBP3 (slow and non-progressive motility). With the logistic regression analysis, it was found that IVEP suffers the effect of SBP1 and SBP2 and a model with these variables was generated to estimate the categories of embryonic production. With the analysis of ANNs, models were generated to estimate IVEP with 18, eight and six predictor variables, and the simplest model included the three sperm subpopulations and the variables plasma and acrosomal membranes integrity, high mitochondrial potential and total defects such as predictors. (AU)

• FAPESP's process: 16/24107-7 - Relationship between sperm subpopulations in Senepol bulls with in vitro production of embryos
• Grantee: Suzane Peres Campanholi
• Support Opportunities: Scholarships in Brazil - Doctorate