Use of a colloid to optimize centrifugation in the selection of bovine sperm for IVF

Abstract

This study aimed to evaluate the effect of the force and duration of centrifugation and the impact of cushioned centrifugation on sperm selection by Percoll gradient, on sperm quality and development kinetics of in vitro produced bovine embryos. Two experiments were performed. In Experiment I, a pool of semen was selected by Percoll gradients and the pellet was divided into four groups and distributed in a 2 × 2 factorial, with two forces (2200 × g or 9000 × g) and two durations (1 min or 3 min) of centrifugation. In Experiment II, semen was divided into two groups and selected by Percoll gradient with Cushion Fluid (CF) or without CF (Control) in the second centrifugation. The morphofunctionality, biochemical characteristics and fertilizing capacity of the selected sperms were evaluated. In addition, the development of the resulting bovine embryos was monitored for 48 h post-insemination. Duncan and Chi-square tests (P < 0.05) were used to compare the means. In Experiment I, there was a significant increase in sperm vigor (P < 0.05) after sperm selection in all treatments. The force and duration of centrifugation did not have any effect on sperm motility, vigor, and recovery rate among the different treatments (P > 0.05). In Experiment II, the recovery rate and reactive oxygen species (ROS) production in semen were similar among treatments (P > 0.05) although a higher ROS production was observed in the CF fertilization medium. Total fertilization rate was superior in the CF group (65.4 ± 5.3%) compared to that in Control (39.6 ± 4.9%). However, the normal fertilization and cleavage rate did not differ between the Control (94 ± 6.3% and 58.3 ± 8.3%) and CF (89 ± 7.1% and 75.0 ± 7.3%) groups. The reduction in the force and duration of centrifugation did not decrease the sperm recovery during selection by the Percoll gradient and the use of CF in the second centrifugation did not affect the normal fertilization and development of bovine IVF embryos up to 48 h. Key words: Bovine embryo. Cushion centrifugation. In vitro production. Percoll gradients. Sperm recovery. ResumoEsse estudo objetivou avaliar o efeito da força e duração da centrifugação, e o impacto da centrifugação amortecida na seleção espermática por gradientes de Percoll, na qualidade espermática e cinética do desenvolvimento de embriões bovinos produzidos in vitro. Dois experimentos foram realizados. No experimento I, um pool de sêmen foi selecionado por gradientes de Percoll e o pellet dividido em quatro grupos e distribuído em um fatorial 2 x 2, com duas forças (2200 e 9000 X g) e dois tempos (1 e 3 min) de centrifugação. No Experimento II, o sêmen foi dividido em dois grupos e selecionado com (CF) ou sem CushionFluid (Controle) na segunda centrifugação. A morfofuncionalidade, características bioquímicas e capacidade fecundante dos espermatozoides selecionados foram avaliadas. Além disso, o desenvolvimento dos embriões bovinos resultantes foi monitorado por 48 horas pós-inseminação. Os testes Duncan e Qui-quadrado (P<0,05) foram usados para ...

High concentrations of β‐hydroxybutyrate alter the kinetics of bovine spermatozoa

“…A Percoll solution was used for the preparation of 90, 60 and 30% solutions with modified Talp‐Fert media (Parrish et al., 1986). The Percoll density gradient was created according to Gonçalves et al., (2018). Briefly, 300 µl thawed semen was layered on the top of the gradient and the tubes were centrifuged twice for 5 min and 1 min at 2.200 × g .…”

“…The Percoll density gradient was created according to Gonçalves et al, (2018). Briefly, 300 µl thawed semen was layered on the top of the gradient and the tubes were centrifuged twice for 5 min and 1 min at 2.200 × g. Finally, the pellet was resuspended in sp-TALP to spermatozoa final concentration of 4 × 10 6 /ml and exposed in different concentrations of BHBA (0.8; 2.4 or 5 mM) or Control for 30, 60, 120 or 180 min.…”