EDITORIAL published: 14 March 2022 doi: 10.3389/fvets.2022.874937 Editorial: The Advances in Semen Evaluation Heriberto Rodriguez-Martinez 1 , Michael Robert McGowan 2 , Szabolcs Nagy 3 and Manuel Alvarez-Rodríguez 1,4* 1 Department of Biomedical and Clinical Sciences (BKV), BKH/Obstetrics and Gynaecology, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden, 2 School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia, 3 Hungarian University of Agriculture and Life Sciences, Keszthely, Hungary, 4 Department of Animal Health and Anatomy, Faculty of Veterinary Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain Keywords: semen, fertility, cryopreservation, animal production, OMICS Editorial on the Research Topic The Advances in Semen Evaluation Although there have been significant advances in our ability to accurately identify infertile and moderate to severely subfertile breeding males, our ability to accurately identify highly fertile males continues to be quite challenging. Apart from motility and kinetic parameter analysis, a number of studies investigating the impact on fertility outcomes of spermatozoa radical oxidative stress (ROS), Total Antioxidant Capacity (TAC), DNA fragmentation, membrane status (acrosome damage, lipid peroxidation, cholesterol influx, apoptosis-like changes), and capacitation-like status have been conducted. However, there is still a lack of a complete definition of the components of semen, not only the spermatozoa itself but also seminal plasma components that affect fertility outcomes. Thus, the development of new analytical tools to accurately define sperm quality is critical. Edited and reviewed by: In the first paper, Anel-López et al. compared the effects on sperm quality and fertility outcomes Ahmed Tibary, Washington State University, of use of three commonly used antibiotics in ram semen extenders. Using computer assisted sperm United States analysis, sperm motility parameters were significantly lower for semen extended with gentamycin. Further, it was shown that there were no significant differences in fertility outcomes between semen *Correspondence: Manuel Alvarez-Rodríguez extended without an antibiotic vs. semen treated with penicillin-streptomycin, globally the most manualvro@gmail.com commonly used extender antibiotic. This finding was consistent with immediate post-thaw results of simultaneous flow cytometric assessment of sperm viability (Caspase 3 and 7 Activity, ROS Specialty section: generation) and prompts the question, “in the absence of venereal pathogens is the antibiotic This article was submitted to treatment of semen necessary”. In a larger study examining the relationship between a range Animal Reproduction - of conventional and new post-thaw laboratory measures of ram sperm quality, Mendoza et al. Theriogenology, demonstrated that the percentage of intact membrane, non-capacitated (IM-NC) spermatozoa a section of the journal (evaluated using the chlortetracycline assay in combination with ethidium homodimer) in extended Frontiers in Veterinary Science chilled semen used for cervical artificial insemination was positively correlated with fertility Received: 13 February 2022 outcomes.When the analysis was restricted to insemination conducted during the breeding season, Accepted: 14 February 2022 an additional three new measures of sperm quality (oxygen consumption, apoptotic-like markers Published: 14 March 2022 caspase activation) were significantly correlated with fertility outcomes. Modeling indicated that Citation: the use of semen with higher percentages of IM-NC and DNA-intact sperm would result in fertility Rodriguez-Martinez H, McGowan MR, outcomes greater than the population mean. Nagy S and Alvarez-Rodríguez M (2022) Editorial: The Advances in Three papers examined the impact on sperm quality of direct or indirect administration of Semen Evaluation. plant derived medicinal substances. Sobeh et al. reported the findings of a study investigating the Front. Vet. Sci. 9:874937. impact on sperm quality of addition of a polyphenol-rich extract, derived from the bark of Entada doi: 10.3389/fvets.2022.874937 abyssinica, to a standard semen extender. It was concluded that the extracts’s potent antioxidant Frontiers in Veterinary Science | www.frontiersin.org 1 March 2022 | Volume 9 | Article 874937 Rodriguez-Martinez et al. Editorial: Advances in Semen Evaluation capacity contributed to the observed improvement in sperm from two different horse breeds with that of donkeys. Three progressive motility and plasma membrane integrity. Greco et al. distinct sub-populations of motile spermatozoa were defined investigated the effect of administration of Tetrahydrocannabinol for both species. The predominant subpopulation consisted of (THC), maca (a traditional Andean crop), and their combination spermatozoa with very fast velocity characteristics and a linear on testicular tissue and semen parameters in mice. The trajectory with a high beat frequency. natural anti-oxidant properties of maca have been shown to In the first of the four reviews, Khan et al. focused on protect testicular cell membranes and mitochondria from how studies using OMICS technologies (proteomics and oxidative stress. Overall, administration of maca, reduced transcriptomics) can improve our understanding of the the deleterious effect of THC on testicular parenchyma and mechanisms of cryo-injury and cryo-tolerance. Systematic semen production. Mao et al. tested the effect of dietary application of these technologies could contribute to the Echinacea purpurea (EPE) treatment on the reproductive optimization of current farm animal cryopreservation protocols. function of streptozotocin-nicotinamide-induced diabetic The ultimate goal is the identification of biomarkers that rats. EPE treatment significantly increased sperm progressive accurately predict spermatozoa freezability. Continuing this motility and decreased the percentage of sperm abnormalities. focus, Evans et al. examined how lipidomics technologies Interestingly, they demonstrated that feeding of EPE increased could be applied to accurately characterize the fatty acid sperm enzymatic antioxidants (superoxide dismutase, catalase composition and their biological roles in ejaculated, stored, and activities, and glutathione), whereas proinflammatory cytokines, cryopreserved spermatozoa. Özbek et al. reviewed how OMICS such as NO, IL-1b, and TNF-a were decreased. technologies have been and further could be applied to improve Three papers examined the impact of chilled and frozen semen identification and selection of more fertile bulls. The final review storage on sperm quality. Suwimonteerabutr et al. investigated focused on the critical issue of the level of agreement between the impact on sperm quality of the addition of butaphosphan laboratories, specifically for the assessment of the percentage of and cyanocobalamin to a standard semen extender for chilled morphologically normal spermatozoa (Perry). A programme to boar semen. Overall, supplementation of the semen extender support standardized examination of fixed samples of bull semen resulted in significant improvements in progressive motility, by a network of commercial laboratories is described, together sperm viability and plasma membrane integrity through to Day with the standardized reporting of specific abnormalities and the 7 of chilled storage. Using a unique approach Wang et al. maximum percentages of each, based on published reports of investigated the molecular mechanisms of sperm cryoinjury and their impact on fertility. cryoresistance by comparing the piRNA profiles of boar sperm with that of Giant Panda sperm, the latter being known to be quite cryotolerant. They concluded that observed species difference AUTHOR CONTRIBUTIONS in the profiles involved in the cAMP signaling pathway may HR-M, MM, SN, and MA-R contributed to the conceptualization, be responsible for the difference in cryotolerance of boar and writing of the original draft, and review and editing. All authors Giant Panda sperm. Continuing in this theme O’Brien et al. approved the final version of this editorial. investigated whether domestication of ungulates is likely to have altered the sensitivity of their sperm to laboratory manipulation Conflict of Interest: The authors declare that the research was conducted in the and chilled storage. Using principal components analysis they absence of any commercial or financial relationships that could be construed as a showed that mitochondrial membrane integrity, oxidative stress potential conflict of interest. level (percentage of low levels of reactive oxidative species) Publisher’s Note: All claims expressed in this article are solely those of the authors and curvilinear velocity of sperm after chilled storage were the and do not necessarily represent those of their affiliated organizations, or those of most important biomarkers defining differences between the the publisher, the editors and the reviewers. Any product that may be evaluated in sperm of domesticated and wild species of pigs, sheep, and this article, or claim that may be made by its manufacturer, is not guaranteed or goats, respectively. endorsed by the publisher. It is now recognized that instead of semen containing a homogenous population of spermatozoa, it consists Copyright © 2022 Rodriguez-Martinez, McGowan, Nagy and Alvarez-Rodríguez. of subpopulations of spermatozoa related to period of This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums spermatogenesis and spermatozoal maturation. Gacem et is permitted, provided the original author(s) and the copyright owner(s) are credited al., using a computer-aided sperm motility analysis system and that the original publication in this journal is cited, in accordance with accepted recording sequences at high frequency (250 frames per second), academic practice. No use, distribution or reproduction is permitted which does not compared the kinematics of sub-populations of spermatozoa comply with these terms. Frontiers in Veterinary Science | www.frontiersin.org 2 March 2022 | Volume 9 | Article 874937