Deciphering sperm chromatin properties to predict stallion sperm fertility.
Abstract: Although previous studies have examined the relationship between the sperm DNA fragmentation index and fertility in stallions, other aspects of chromatin structure or packaging and fertility have not been explored. In the present study, relationships between fertility and DNA fragmentation index, protamine deficiency, total thiols, free thiols and disulfide bonds in stallion spermatozoa were investigated. Ejaculates (n = 36) were collected from 12 stallions and extended to prepare semen doses for insemination. One dose from each ejaculate was sent to the Swedish University of Agricultural Sciences. Aliquots of semen were stained for flow cytometry with acridine orange for the Sperm Chromatin Structure Assay (DNA fragmentation Index, %DFI), with chromomycin A3 (CMA) for protamine deficiency, and with monobromobimane (mBBr) for detection of total and free thiols and disulfide bonds. Per season pregnancy rates after insemination were obtained. Mixed linear models were used to analyze data. Negative correlations were found between pregnancy rate and %DFI (r = -0.35, P < 0.03) and pregnancy rate and free thiols (r = -0.60, P < 0.0001). Furthermore, there were positive correlations between total thiols and disulfide bonds (r = 0.95, P < 0.0001), and protamine and disulfide bonds (r = 0.4100, P < 0.01986). Since chromatin integrity, protamine deficiency and packaging were all associated with fertility, a combination of these factors could be used as a biomarker of fertility when assessing ejaculates.
Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.
Publication Date: 2023-02-16 PubMed ID: 36801727DOI: 10.1016/j.anireprosci.2023.107200Google Scholar: Lookup
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- Journal Article
Summary
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The research investigates the relationship between certain qualities of stallion sperm chromatin and its fertility. It establishes that chromatin integrity, protamine deficiency, packaging of sperm, and certain chemical properties might serve as biomarkers for assessing stallion fertility.
Objectives and Methodology
- The study seeks to understand the correlation between stallion fertility and various chromatin properties such as DNA fragmentation index, protamine deficiency, total thiols, free thiols, and disulfide bonds in spermatozoa.
- A total of 36 ejaculates were obtained from 12 stallions and were then extended to create semen doses.
- Every dose from each independent ejaculate was sent to the Swedish University of Agricultural Sciences where aliquots were stained for various tests. Three stains were used: acridine orange for the Sperm Chromatin Structure Assay, chromomycin A3 for detecting protamine deficiency, and monobromobimane for identifying total and free thiols and disulfide bonds.
- Per season fertility rates were then secured after insemination.
- A mixed linear model was utilized in the data analysis phase.
Results and Findings
- The study found negative correlations between pregnancy rates and the DNA fragmentation index, meaning that a higher fragmentation index yielded lower successful pregnancies. The same negative correlation was found between pregnancy rates and free thiols in sperm, where more free thiols meant less pregnancy success.
- On the other hand, positive correlations were observed between total thiols and disulfide bonds as well as between protamine and disulfide bonds, meaning higher values for these were associated with higher fertility.
- These findings suggest that the integrity of chromatin, the deficiency of protamine, and the packaging of the sperm can be used as biomarkers when evaluating stallion ejaculates for fertility.
Conclusion
- The research concludes that there are several properties of sperm chromatin that can be considered when trying to predict stallion fertility. These include the DNA fragmentation index, free and total thiols, and disulfide bonds.
- By using these properties as potential biomarkers, the research contributes significantly to improving methods of evaluating and predicting stallion fertility.
Cite This Article
APA
Al-Kass Z, Ntallaris T, Morrell JM, Johannisson A.
(2023).
Deciphering sperm chromatin properties to predict stallion sperm fertility.
Anim Reprod Sci, 250, 107200.
https://doi.org/10.1016/j.anireprosci.2023.107200 Publication
Researcher Affiliations
- Clinical Sciences, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden; Department of Surgery and Theriogenology, College of Veterinary Medicine, University of Mosul, Mosul, Iraq.
- Clinical Sciences, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
- Clinical Sciences, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden. Electronic address: jane.morrell@slu.se.
- Clinical Sciences, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
MeSH Terms
- Pregnancy
- Female
- Male
- Animals
- Horses
- Chromatin
- Semen
- Biofilms
- DNA Fragmentation
- Bioreactors
- Fertility
- Spermatozoa
- Protamines
- Sulfhydryl Compounds
- Disulfides
Conflict of Interest Statement
Conflict of Interest The authors have no conflict of interest to declare.
Citations
This article has been cited 5 times.- Strassner FM, Demattio L, Siuda M, Malama E, Muffels G, Bollwein H. Relationships Between Metabolism of Cryopreserved Equine Sperm Determined by the Seahorse Analyzer and Sperm Characteristics Measured by Flow Cytometry and Computer-Assisted Analysis of Motility. Vet Sci 2025 Nov 21;12(12).
- Abah KO, Ligocka-Kowalczyk Z, Itodo JI, Ameh G, Partyka A, Nizanski W. Association between sperm DNA fragmentation and fertility parameters in farm animals: a systematic review and meta-analysis. BMC Vet Res 2025 Mar 26;21(1):204.
- Ren H, Wen X, He Q, Yi M, Dugarjaviin M, Bou G. Comparative Study on the Sperm Proteomes of Horses and Donkeys. Animals (Basel) 2024 Jul 31;14(15).
- Babaei K, Aziminezhad M, Mirzajani E, Mozdarani H, Sharami SH, Norollahi SE, Samadani AA. A critical review of the recent concept of regulatory performance of DNA Methylations, and DNA methyltransferase enzymes alongside the induction of immune microenvironment elements in recurrent pregnancy loss. Toxicol Rep 2024 Jun;12:546-563.
- Johannisson A, Morrell JM, Ntallaris T. A combination of biomarkers for predicting stallion sperm fertility. Vet Res Commun 2024 Aug;48(4):2157-2169.
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