Sperm Sexing Mediated by Magnetic Nanoparticles in Donkeys, a Preliminary In Vitro Study

Preselection of sex before conception has been one of the objectives pursued by scientists and breeders for many years. The donkey milk industry has shown a greater commercial interest, since jennies' demand is increasing nowadays. Therefore, to get a female animal, the oocyte must be fertilized with previously sexed semen. The current technique used for sperm sexing separates spermatozoa containing the X or Y chromosome based on each cell DNA content. However, this technique exposes spermatozoa to high-pressure speed flow, DNA fluorescent stain, and UV light, factors that may affect sperm quality. The aim of this study was to test a new technique to isolate spermatozoa carrying the X chromosome by means of magnetic nanoparticles (MNPs). Results show that the MNP technique is highly effective in select X spermatozoa, without affecting several physiological sperm parameters. In conclusion, the MNP technique provides an X sperm population with similar sperm physiological state than the control sample. The new sexing technology presented here can be mainly applied to improve the donkey's milk industry.