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The “dilution effect” in stallion sperm.
Abstract: Dilution of semen to less than 20 × 10(6) sperm/mL has been reported to decrease sperm quality in multiple species, a phenomenon known as the semen "dilution effect." Critical evaluation of stallion semen diluted to these concentrations, however, has not been reported. This study evaluated sperm motion characteristics (percent total motility [TMOT], percent progressive motility [PMOT], curvilinear velocity [μm/s], and percent straightness) and plasma membrane integrity (percent plasma membrane intact [PMI]) in semen samples diluted to 2.5 × 10(6) sperm/mL with the addition of 0%, 7.5%, or 25% seminal plasma (groups T-2.5/0, T-2.5/7.5, and T-2.5/25, respectively), or after simple dilution to 30 × 10(6) sperm/mL (group T-30), or simple dilution to a ratio of 3:1 (extender:semen; group T-3:1SD). Evaluations were performed immediately after semen collection (T0), and after 24 and 48 hours of cooled storage (T24 and T48, respectively). The PMI and TMOT were the highest in group T-3:1SD at T0. At T24, the PMI in groups T-30, T3:1SD and T3:1/30, and T-2.5/0 were higher than that in the other groups (P < 0.05), whereas TMOT in group T-3:1SD was higher (P 0.05), whereas PMOT was the highest in groups T-2.5/0 and T-2.5/7.5 (P < 0.05). These findings revealed that treatments in which semen was diluted to a concentration of 2.5 × 10(6) sperm/mL had lower initial PMI, TMOT, and PMOT, but semen quality did not decline after 24 and 48 hours of cooled storage. In this study, TMOT and PMI in dilute semen were less than those in more concentrated semen at T0. This effect, while significant, was small and less apparent after cooled storage.
Copyright © 2015 Elsevier Inc. All rights reserved.
Publication Date: 2014-11-15 PubMed ID: 25543156DOI: 10.1016/j.theriogenology.2014.11.012Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research studied the effect of dilution on the quality of stallion sperm, finding that while the initial dilution decreased sperm quality, the quality did not decline further after being cooled and stored for 24 and 48 hours.
Explanation of the Research
The research focused on a common phenomenon observed in several species, the “semen dilution effect”, wherein the quality of semen decreases when it is diluted to less than 20 × 10(6) sperm/mL.
- This phenomenon has not been critically studied in stallion sperm previously.
- The researchers tested multiple aspects of sperm quality including sperm motility, progressive motility, curvilinear velocity, straightness, and plasma membrane integrity.
- Dilution was carried out to 2.5 × 10(6) sperm/mL with 0%, 7.5%, and 25% seminal plasma added or simple dilution to 30 × 10(6) sperm/mL or to a 3:1 ratio of extender:semen.
- The parameters were tested immediately after collection and after 24 and 48 hours of cooled storage.
Key Findings
The key findings of the study include observations on the effect of dilution on various sperm characteristics:
- Immediately after collection (T0), the integrity of the plasma membrane (PMI) and total motility (TMOT) were highest when semen was diluted to a 3:1 ratio of extender:semen.
- At 24 hours (T24), PMI was highest in samples diluted to 30 × 10(6) sperm/mL and in a 3:1 ratio of extender:semen, as well as in the group where the sample was simply diluted to 2.5 × 10(6) sperm/mL without any seminal plasma added.
- At the same time point, TMOT was also higher in the group diluted to a 3:1 extender:semen ratio than in any other groups except the one diluted to 30 × 10(6) sperm/mL.
- At 48 hours (T48), there were no differences in PMI between the groups diluted to a 3:1 extender:semen ratio, 30 × 10(6) sperm/mL, and 2.5 × 10(6) sperm/mL sans seminal plasma.
- Progressive motility (PMOT) was highest in samples diluted to 2.5 × 10(6) sperm/mL without seminal plasma and 7.5% seminal plasma.
- In general, the initial dilution decreased sperm quality as observed by lower PMI, TMOT, and PMOT; but semen quality did not decline further post-cooled storage for 24 and 48 hours.
- These findings highlight that while sperm quality decreases immediately after dilution, it manages to stabilize during subsequent cooled storage.
Implication of the Findings
- The research adds valuable data on stallion sperm, which has been lacking despite similar studies in other species.
- It also provides practical insights for situations requiring semen storage and transportation.
Cite This Article
APA
Hayden SS, Blanchard TL, Brinsko SP, Varner DD, Hinrichs K, Love CC.
(2014).
The “dilution effect” in stallion sperm.
Theriogenology, 83(4), 772-777.
https://doi.org/10.1016/j.theriogenology.2014.11.012 Publication
Researcher Affiliations
- Heartland Equine Hospital, Tonganoxie, Kansas, USA.
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA. Electronic address: clove@cvm.tamu.edu.
MeSH Terms
- Animals
- Horses / physiology
- Insemination, Artificial / veterinary
- Male
- Semen Analysis / veterinary
- Semen Preservation / veterinary
- Spermatozoa / physiology
Citations
This article has been cited 10 times.- Madeddu M, Marelli S, Abdel Sayed A, Mosca F, Cerolini S, Zaniboni L. Assessment of Sperm Viability and Computer-Assisted Motility Analysis in Budgerigars (Melopsittacus undulatus): Effect of Several In Vitro Processing Conditions. Vet Med Int 2022;2022:5997320.
- Ramirez-Perez H, Guerrero-Netro HM, Torres-Rodríguez P, Díaz-Durán M, Boeta-Acosta AM, Diaw M. A combination of taurine and caffeine maintains sperm quality in equine semen during chilled storage. J Adv Vet Anim Res 2021 Dec;8(4):635-641.
- Gimeno BF, Bariani MV, Laiz-Quiroga L, Martínez-León E, Von-Meyeren M, Rey O, Mutto AÁ, Osycka-Salut CE. Effects of In Vitro Interactions of Oviduct Epithelial Cells with Frozen-Thawed Stallion Spermatozoa on Their Motility, Viability and Capacitation Status. Animals (Basel) 2021 Jan 3;11(1).
- Gacem S, Catalán J, Valverde A, Soler C, Miró J. Optimization of CASA-Mot Analysis of Donkey Sperm: Optimum Frame Rate and Values of Kinematic Variables for Different Counting Chamber and Fields. Animals (Basel) 2020 Oct 29;10(11).
- El Kadili S, Kirschvink N, Raes M, Bister JL, Archa B, Douaik A, Chentouf M. Influence of Season and Liquid Storage at 16 °C on Beni Arouss Bucks' Semen Quality. Animals (Basel) 2020 Oct 29;10(11).
- Shawky M, Fawy AF, Elomda AM, Elmenawey MA, Atta AEM, Abbas AO, Mehaisen GMK. Effect of semen dilution rate and dimethyl acetamide levels on post-thaw motility and fertility parameters of rooster sperm. PLoS One 2025;20(10):e0335748.
- Hackerova L, Pilsova A, Pilsova Z, Zelenkova N, Tymich Hegrova P, Klusackova B, Chmelikova E, Sedmikova M, Simonik O, Postlerova P. Boar Sperm Motility Assessment Using Computer-Assisted Sperm Analysis: Current Practices, Limitations, and Methodological Challenges. Animals (Basel) 2025 Jan 22;15(3).
- Álvarez-Rodríguez M, Tomás-Almenar C, Nieto-Cristóbal H, de Mercado E. Evaluation of Different Thawing Protocols on Iberian Boar Sperm Preserved for 10 Years at Different Liquid Nitrogen Levels. Animals (Basel) 2024 Mar 15;14(6).
- Zhang L, Wang X, Jiang C, Sohail T, Sun Y, Sun X, Wang J, Li Y. Effect of Different Dilution Methods and Ratios of Ram Semen on Sperm Parameters after Cryopreservation. Animals (Basel) 2024 Mar 15;14(6).
- Jiang S, Huang F, Niu P, Wang J, He X, Han C, Gao Q. Preservation of Simmental bull sperm at 0°C in Tris dilution: effect of dilution ratio and long-distance transport. Anim Biosci 2024 Feb;37(2):203-209.
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