High percentage of midpiece defects in Brangus bull sperm with no reduction in sperm kinematics.

The study investigated midpiece defects in sperm from a 5-year-old Brangus bull with a high rate of semen batch rejection, due to morphologically abnormal sperm, with no reduction in sperm kinematics. A comprehensive evaluation was conducted over a 16-month period, involving 28 ejaculates. Notably, despite the high proportion of midpiece defects (average 37.73%, from 3% to 58%), the study revealed stable sperm production, with no discernible differences in the kinematic data before and after cryopreservation. Electron microscopy identified discontinuities in the mitochondrial sheath, characteristic of midpiece aplasia (MPA). The anomalies were attributed to be of genetic origin, as other predisposing factors were absent. Additionally, the electron microscopy unveiled plasma membrane defects, vacuoles and chromatin decondensation, consistent with previous findings linking acrosome abnormalities with midpiece defects. The findings underscored the necessity of conducting thorough laboratory evaluations before releasing cryopreserved semen for commercialization. Despite substantial morphological alterations, the initial semen evaluation data indicated acceptable levels of sperm kinematics, emphasizing the resilience of sperm production to severe morphological changes. This case report serves as a contribution to the understanding of midpiece defects in bull sperm, emphasizing the need for meticulous evaluation and quality control in semen processing and commercialization.

Comparação de diluidores comerciais na motilidade, funcionalidade e integridade da membrana plasmática do espermatozoide bovino / Comparison of commercial diluents on motility, functionality and integrity of plasma membrane of bovine spermatozoa

O objetivo do estudo foi comparar o efeito de três diluidores comerciais (Tryladil®, Botu-Bov® e OptiXcell®) na qualidade do espermatozoide bovino após o processo de criogenia. Para tal, foram utilizados oito touros da raça Nelore (2 ejaculados/touro). As amostras de sêmen fresco, diluído e pós-descongelamento foram avaliadas, comparando os parâmetros de motilidade total, vigor, funcionalidade da membrana (HOST) e integridade da membrana (eosina). Os dados foram expressos em média e desvio padrão. As variáveis foram submetidas às análises de ANOVA e Tukey ou teste de Friedman e Dunn's, dependendo da normalidade (p< 0,05). Os achados mostram que no momento da diluição não houve diferença (p˃0,005) entre os diluidores comerciais nos parâmetros avaliados (exceto integridade da membrana plasmática). No entanto, no momento do pós-descongelamento os espermatozoides criopreservados utilizando-se o diluidor Tryladil® apresentaram maiores valores (p˂0,005) referentes a integridade e funcionalidade da membrana plasmática comparado aos diluídos em Botu-Bov® e OptIXcell®. Os parâmetros relacionados a cinética espermática (motilidade e vigor) não se diferiram (p˃0,005) entre os diluidores comerciais utilizados. Em conclusão, no momento pós-descongelamento o diluidor Tryladil® apresentou os melhores resultados nos parâmetros de integridade e funcionalidade da membrana plasmática. Sendo assim, recomenda-se o diluidor Tryladil® para criopreservação de sêmen de bovinos da raça Nelore.

The main of the study was to compare the quality of frozen bull semen processed with three different commercially extenders (Tryladil®, Botu-Bov® and OptiXcell®). For this, eight Nelore bulls (two ejaculate per bull). Sperm samples were analyzed fresh, diluted and frozen-thawed. The parameters analyzed were total motility, sperm vigor, functional integrity of sperm plasma membrane (HOST) and plasma membrane integrity (eosin). Date were expressed as mean and standard deviation. The variables were subjected to ANOVA (Tukey test) or Friedman (Dunn's test) test according to normality (p< 0,05). The results indicate that there was no difference (p˃0,005) among all treatments in the parameters evaluated (except plasma membrane integrity) at dilution moment. However, Tryladil extender promoted an increase (p˂0,005) in functional and integrity of sperm plasma membrane compared with others extenders at the post-thawing analyze. After thawing, there was no difference (p˃0,005) among all treatments in the kinetic parameters. In conclusion, the Tryladil® extender promoted an increase in functional and integrity of frozen-thawed sperm plasma membrane. Therefore, the Tryladil® extender is recommended to be use as an extender for Nelore bull sperm cryopreservation.