31 Evaluation of in vitro-produced bovine embryos with conventional and SexedULTRA-4M X and Y chromosome-bearing semen: survival after slow freezing for direct transfer
H. Álvarez-Gallardo A B , M. Kjelland C D , M. Pérez-Martínez E , A. Velázquez-Roque F , F. Villaseñor-González G and S. Romo AA Facultad de Estudios Superiores Cuautitlán, UNAM, Cuautitlán, México, México
B Centro Nacional de Recursos Genéticos, INIFAP, Tepatitlán, Jalisco, México
C Conservation, Genetics & Biotech LLC, Valley City, ND, USA
D Mayville State University, Mayville, ND, USA
E Facultad de Medicina Veterinaria y Zootecnia, UNAM, CDMX, México
F Private practice, Servicios Integrados Ganaderos, Monterrey, Nuevo León, México
G Campo Experimental Centro Altos de Jalisco, INIFAP, Tepatitlán, Jalisco, México
Reproduction, Fertility and Development 34(2) 250-250 https://doi.org/10.1071/RDv34n2Ab31
Published: 7 December 2021
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
The transfer of cryopreserved embryos has great potential to disseminate valuable genetics in cattle; however, a suitable protocol for cryopreservation of in vitro-produced embryos (IVP) for direct transfer is still being improved. The combination of IVP and cryopreservation can be further enhanced when associated with the new sexed semen technology known as SexedULTRA-4M™ (STgenetics). We previously reported no differences in bovine in vitro embryo production when using conventional (CONV) or SexedULTRA-4M semen (ULTRA-4M); however, it is also important to evaluate blastocyst cryopreservation from CONV and ULTRA-4M embryos. The objective of this research was to evaluate slow-freezing cryotolerance (ethylene glycol) of IVP embryos produced with CONV, SexedULTRA-4M X chromosome-bearing (ULTRA X), and SexedULTRA-4M Y chromosome-bearing (ULTRA Y) semen. The research was carried out in the reproduction laboratory at the Palominos Ranch (Jalisco, México). The IVP was performed using a continuous in vitro culture system based on Vitrogen™ media. Bovine embryos were produced with CONV, ULTRA X, and ULTRA Y semen from the same bull and from contemporaneous ejaculates, using slaughterhouse ovaries. On Day 7 of in vitro culture, expanded blastocyst stage embryos (n = 300; 100 for CONV, 100 for ULTRA X, and 100 for ULTRA Y) quality 1 and 2 were subjected to a controlled-rate freezing curve after equilibration for 8 to 10 min in freezing medium (ethylene glycol Freeze Plus Vigro™), starting at −6°C (seeding), decreasing by 0.5°C min−1, ending at −32°C, and then plunging directly in liquid nitrogen. All embryos (300) were thawed (10 s in air and 20 s in water at 30°C) and cultured for 48 h at 38.5°C, 5% CO2, 5% O2, and 90% N2 at 100% humidity. Re-expansion and hatching rates were evaluated at 24 and 48 h. Statistical analysis was carried out using the chi-squared procedure in Jamovi software (version 1.2; The Jamovi Project). Re-expansion rates at 24 h were 61%, 66%, and 65%, and at 48 h were 21%, 22%, and 18%, respectively, for CONV, ULTRA X, and ULTRA Y. The percentages of hatching (from those that re-expanded) were 62%, 60%, and 63% at 24 h, and 14%, 18%, and 17% at 48 h, respectively, for CONV, ULTRA X, and ULTRA Y. There were no significant differences between the groups (P > 0.05) for all variables analysed. In conclusion, under the conditions of this research, ULTRA-4M and CONV had similar results concerning slow freezing for direct transfer of IVP bovine embryos.
|
