175 Analysis of Cryopreserved Semen Quality: With the Tools Available, What Is Possible to Be Interpreted

Abstract

Abstract Identifying doses of post-thawed semen with high and low fertility potential is the main objective pursued by professionals and companies involved in commercializing frozen semen. In post-thaw semen, we can evaluate the motility characteristics and the integrity of the spermatozoa membranes and their DNA so that we can identify the number of cells that have the minimum characteristics to be considered with the potential to fertilize the oocyte. However, even with these analyzes using fluorescent probes, flow cytometry, and a computerized semen analysis system, it is impossible to predict the dose’s fertilizing potential accurately. The spermatozoa and seminal plasma originate from an individual (e.g., boar, bull, stallion), and even the spermatozoa and seminal plasma from this individual are different between different ejaculates. Factors such as genetics, age, ambiance, nutrition, and semen manipulation can alter the cryotolerance capacity of a given ejaculate, thus affecting its fertility potential. However, recent studies with assessments of proteomics, lipidomics, metabolomics, and miRNAs have associated cryotolerance and semen fertility with markers that can be evaluated before the ejaculate cryopreservation process—in this way, creating the possibility of selecting high fertility doses before the freezing process. Suppose these biological markers will conclusively make it possible to inform whether post-thawed semen dose has high or low fertility potential. In that case, only future research work verifying fertility will allow us to know. In the meantime, it is highly recommended to evaluate the post-thaw semen by assessing characteristics of motility, the integrity of the plasma and acrosomal membranes, and the integrity of DNA. Thus, ensuring that inseminations are carried out with the minimum number of sperm able to provide a high potential for fertility. These minimum numbers are related to the species and type of cryopreserved semen: conventional or sexed.