CALIDAD SEMINAL Y EXPRESIÓN DE ARNM PLCZ1 EN CÉLULAS ESPERMÁTICAS DE TOROS CRIOLLO CHIHUAHUENSE V/S EUROPEO.

RONQUILLO ROACHO, LUIS MIGUEL (2021) CALIDAD SEMINAL Y EXPRESIÓN DE ARNM PLCZ1 EN CÉLULAS ESPERMÁTICAS DE TOROS CRIOLLO CHIHUAHUENSE V/S EUROPEO. Maestría thesis, UNIVERSIDAD AUTONOMA DE CHIHUAHUA.

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Resumen

Sperm motility and kinematics analyzes are important to predict bull fertility; however, there are other molecules in the sperm with the ability to improve the pregnancy rate. For example, PLCZ1 is a protein from sperm that plays a unique role in the activation of the zygote and is important in the survival of the embryo, ensuring that the gestation reaches term. Furthermore, it has been reported that there is a positive relationship between the levels of the PLCZ1 protein and the levels of its mRNA. The aim of the study was to evaluate seminal motility, sperm kinematics and determine the expression of PLCZ1 mRNA in sperm cells of Chihuahuense Criollo bulls and European bulls, under low-input production conditions. The study was carried out in two stages that correspond to independent experiments. In stage 1, the motility and kinematics of the refrigerated and post-thawed semen were characterized in four Criollo and four Angus bulls. With two ejaculates per bull every five days. In stage 2, mass and individual motility was evaluated, as well as the expression of PLCZ1 mRNA in the sperm cells of three Criollo and three European bulls at two seasons of the year (winter and summer); from each bull, three ejaculates were collected at intervals of five days for each season. The statistical analyzes in Stage 1 were carried out with the PROC MIXED of SAS, having as fixed factors the breed and state of semen (refrigerated and post-thawed) and as a random effect to the bull. No differences were found by racial group in motility or sperm kinematics. Total motility was higher (P <0.05) in refrigerated semen compared to post-thaw (54.4 ± 5.9 vs 32.3 ± 5.9 %). In sperm kinematics, a difference (P <0.05) was found in speed variables such as: VAP and VCL, as well as in: DCL, STR, LIN, ALH and WOB by state of the semen. Statistical analyzes for Stage 2 were performed with the PROC GLM of SAS, having race and season as fixed factors. No differences were found in individual motility by racial group or season, however, group motility was higher (P <0.05) in European cattle during winter (76.6 ± 2.8 vs 71.1 ± 2.8 %) and this difference was more pronounced during the summer (77.7 ± 2.8 vs 58.88 ± 2.8 %), having an interaction effect. The expression of PLCZ1 mRNA, relative to β-actin was 5.3 times higher (P <0.05) in winter (5.09 ± 1.09) compared to summer (0.96 ± 1.09). A tendency (P = 0.12) is projected to be higher the levels of PLCZ1 mRNA in Creole cattle with respect to the European one (4.36 ± 1.09 vs 1.69 ± 1.09). It is concluded that the molecular analysis of semen in addition to the indicators of a fertility test is important, since, with similar motility values, bulls can present different levels of expression of PLCZ1 mRNA.

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