This is an early access version, the complete PDF, HTML, and XML versions will be available soon.
Molecular Constraints of Sperm Sex Sorting via TLR7/8 Activation
by
, , , ,
Alikhan Magauiya
1,2,
Kausar Torebek
1,2,
Filipp Georgijevič Savvulidi
3,*
,
Martin Ptáček
3
,
Christopher LeBrun
3,
Lucie Langerová
3,
Elbosyn Sagdat
1,
Saltanat Baikoshkarova
4,5 and
Nurlan Malmakov
1 1
Meat Sheep Breeding Department, Kazakh Research Institute of Livestock and Fodder Production, Almaty 050 035, Kazakhstan
2
Ecomed-Shymkent, Shymkent 160 023, Kazakhstan
3
Department of Animal Science, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences (CULS), 165 00 Prague, Czech Republic
4
Ecomed, Almaty 050 009, Kazakhstan
5
New Generation Clinic, Almaty A15E2H1, Kazakhstan
*
Author to whom correspondence should be addressed.
Animals 2025, 15(20), 2976; https://doi.org/10.3390/ani15202976 (registering DOI)
Submission received: 8 September 2025
/
Revised: 10 October 2025
/
Accepted: 10 October 2025
/
Published: 14 October 2025
(This article belongs to the Special Issue Sperm Preservation and Sexing Technologies in Large- and Small-Ruminant Reproduction: Current Status and Future Perspectives)
Simple Summary
Sperm sex selection is important in livestock for economic reasons. The current method, Fluorescence-Activated Cell Sorting (FACS), is costly and can harm sperm. A newer, cheaper method uses TLR7/8 receptors to slow down X-bearing sperm, allowing Y-bearing sperm to be separated using the swim-up technique. This method works well in murine, caprine, ovine, and bovine species, but not in swine and canine species due to species-specific differences. This review explores the possible reasons behind those differences.
Abstract
In modern livestock, the demand for sperm sex selection technologies is high, as the ability to deliberately produce offspring of a specific sex offers significant economic advantages. Traditionally, sperm sorting is performed using Fluorescence-Activated Cell Sorting. However, the flow cytometric method is expensive, technically complex, and associated with reduced sperm viability. An alternative promising method involves the use of Toll-like TLR7/8 receptors for the selective binding of spermatozoa of a particular sex. It was discovered previously that the activation of TLR7/8 by its ligand(s) selectively inhibits the motility of X-bearing sperm without affecting the motility of Y-bearing sperm. The swim-up technique, which separates sperm based on sex chromosome type by isolating fractions enriched in either X- or Y-bearing gametes due to differences in their motility, can be used with this method. Sperm sex sorting via the TLR7/8 activation is cheap, technically non-complex, and does not affect sperm viability negatively. The goal of this review is to provide an overview of the TLR7/8-dependent sperm sorting method. Further, we discuss why the method of sperm sorting via TLR7/8 activation is successfully implemented in some animal species (such as murine, caprine, ovine, and bovine) but fails in others, like swine and canine.
