{"title":"Reproductive physiology of the boar: What defines the potential fertility of an ejaculate?","authors":"","doi":"10.1016/j.anireprosci.2024.107476","DOIUrl":null,"url":null,"abstract":"<div><div>Despite decades of research and handling of semen for use in artificial insemination (AI) and other assisted reproductive technologies, 5–10% of selected boar sires are still considered sub-fertile, escaping current assessment methods for sperm quality and resilience to preservation. As end-product, the ejaculate (emitted spermatozoa sequentially exposed to the composite seminal plasma, the SP) ought to define the homeostasis of the testes, the epididymis, and the accessory sexual glands. Yet, linking findings in the ejaculate to sperm production biology and fertility is suboptimal. The present essay critically reviews how the ejaculate of a fertile boar can help us to diagnose both reproductive health and resilience to semen handling, focusing on methods -available and under development- to identify suitable biomarkers for cryotolerance and fertility. Bulk SP, semen proteins and microRNAs (miRNAs) have, albeit linked to sperm function and fertility after AI, failed to enhance reproductive outcomes at commercial level, perhaps for just being components of a complex functional pathway. Hence, focus is now on the interaction sperm-SP, comparing <em>in vivo</em> with <em>ex vivo</em>, and regarding nano-sized lipid bilayer seminal extracellular vesicles (sEVs) as priority. sEVs transport fragile molecules (lipids, proteins, nucleic acids) which, shielded from degradation, mediate cell-to-cell communication with spermatozoa and the female internal genital tract. Such interaction modulates essential reproductive processes, from sperm homeostasis to immunological female tolerance. sEVs can be harvested, characterized, stored, and manipulated, e.g. can be used for andrological diagnosis, selection of breeders, and alternatively be used as additives to improve cryosurvival and fertility.</div></div>","PeriodicalId":7880,"journal":{"name":"Animal Reproduction Science","volume":"269 ","pages":"Article 107476"},"PeriodicalIF":2.2000,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Animal Reproduction Science","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0378432024000678","RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"AGRICULTURE, DAIRY & ANIMAL SCIENCE","Score":null,"Total":0}
引用次数: 0
Abstract
Despite decades of research and handling of semen for use in artificial insemination (AI) and other assisted reproductive technologies, 5–10% of selected boar sires are still considered sub-fertile, escaping current assessment methods for sperm quality and resilience to preservation. As end-product, the ejaculate (emitted spermatozoa sequentially exposed to the composite seminal plasma, the SP) ought to define the homeostasis of the testes, the epididymis, and the accessory sexual glands. Yet, linking findings in the ejaculate to sperm production biology and fertility is suboptimal. The present essay critically reviews how the ejaculate of a fertile boar can help us to diagnose both reproductive health and resilience to semen handling, focusing on methods -available and under development- to identify suitable biomarkers for cryotolerance and fertility. Bulk SP, semen proteins and microRNAs (miRNAs) have, albeit linked to sperm function and fertility after AI, failed to enhance reproductive outcomes at commercial level, perhaps for just being components of a complex functional pathway. Hence, focus is now on the interaction sperm-SP, comparing in vivo with ex vivo, and regarding nano-sized lipid bilayer seminal extracellular vesicles (sEVs) as priority. sEVs transport fragile molecules (lipids, proteins, nucleic acids) which, shielded from degradation, mediate cell-to-cell communication with spermatozoa and the female internal genital tract. Such interaction modulates essential reproductive processes, from sperm homeostasis to immunological female tolerance. sEVs can be harvested, characterized, stored, and manipulated, e.g. can be used for andrological diagnosis, selection of breeders, and alternatively be used as additives to improve cryosurvival and fertility.
期刊介绍:
Animal Reproduction Science publishes results from studies relating to reproduction and fertility in animals. This includes both fundamental research and applied studies, including management practices that increase our understanding of the biology and manipulation of reproduction. Manuscripts should go into depth in the mechanisms involved in the research reported, rather than a give a mere description of findings. The focus is on animals that are useful to humans including food- and fibre-producing; companion/recreational; captive; and endangered species including zoo animals, but excluding laboratory animals unless the results of the study provide new information that impacts the basic understanding of the biology or manipulation of reproduction.
The journal''s scope includes the study of reproductive physiology and endocrinology, reproductive cycles, natural and artificial control of reproduction, preservation and use of gametes and embryos, pregnancy and parturition, infertility and sterility, diagnostic and therapeutic techniques.
The Editorial Board of Animal Reproduction Science has decided not to publish papers in which there is an exclusive examination of the in vitro development of oocytes and embryos; however, there will be consideration of papers that include in vitro studies where the source of the oocytes and/or development of the embryos beyond the blastocyst stage is part of the experimental design.