Sperm kinetic subpopulations in samples from Angus and Holstein bulls vary differentially in a longitudinal assay

TERAN ESTER; PIROSANTO YAMILA; TRIBULO PAULA; MANUEL RAMON; ALICIA ANTONINI; MOLINA ANTONIO; DEMYDA-PEYRÁS, SEBASTIÁN

Lima

Congreso; 49th international Embryo Tecnology Society; 2023

Heterogeneity is an intrinsic property of mammalian sperm, whose role in reproductive performance could be meaningful. Computer-assisted sperm analysis (CASA) has allowed to analyze this diversity by determining the existence of subpopulations (Sp) with specific kinematic characteristics. Despite such Sp can differ among individuals even batches, it was suggested the existence of specific patterns by breed. Hereby we analyzed and compared the sperm subpopulation patterns over time in post-thawed samples from Angus and Holstein breeds. We analyzed 132 sperm samples from 35 Angus and 31 Holstein bulls (two replicates from different batches) in a longitudinal study at three different time points, after thawing: T0 (five min), T1 (60 min), and T2 (120 min). Eight parameters were measured using a CASA system (AndroVision®): curvilinear velocity (VCL, μm/s), straight-line velocity (VSL, μm/s); average path velocity (VAP, μm/s), linearity (LIN, %: VSL/VCL), straightness (STR, %: VSL/VAP), wobble coefficient (WOB, %: VAP/VCL), mean amplitude of lateral head displacement (ALH, μm) and beat-cross frequency (BCF, Hz). Data obtained (446,836 motile sperm) were analyzed by performing a two-step multivariate non-hierarchical - hierarchical analysis to determine Sp. Differences between Sp by breed and time were analyzed using a Z-test. We identified four sperm Sp: Sp1: rapid and highly progressive sperm, with high-velocity values, high LIN, STR, WOB, BCF, and low ALH; Sp2: intermediate and progressive sperm, which showed medium VCL, VSL, VAP, ALH, and BCF but high LIN, STR and WOB; Sp3: slow and non-progressive sperm, with the lowest values of VSL, VAP, BCF, LIN and WOB; and Sp4: highly active but non-progressive sperm, characterized by the highest VCL ans ALH, high VSL, VAP, and BCF but low LIN, STR and WOB. Sp1 and Sp2 were greater in Holstein, whereas Sp3 and Sp4 greater in Angus (Table 1). Interestingly, at T1, the percentage of Sp4 increased significantly (p