66 The production of ovine embryos in vitro using frozen-thawed semen processed in the breeding and nonbreeding seasons
G. Márquez-Márquez A , S. Romo-Domínguez B , A. Velázquez-Roque C , H. Álvarez-Gallardo D E , M. Kjelland F G , F. Villaseñor-González H and S. Romo DA Private practice, Granos y Servicios Integrales SA de CV, Jalisco, México
B Facultad de Medicina Veterinaria y Zootecnia, UNAM, CDMX, México
C Private practice, Servicios Integrados Ganaderos, Monterrey, Nuevo León, México
D Facultad de Estudios Superiores Cuautitlán, UNAM, Cuautitlán, Estado de México, México
E Centro Nacional de Recursos Genéticos, INIFAP, Tepatitlán, Jalisco, México
F Conservation, Genetics & Biotech LLC, Valley City, ND, USA
G Mayville State University, Mayville, ND, USA
H Campo Experimental Centro Altos de Jalisco, INIFAP, Tepatitlán, Jalisco, México
Reproduction, Fertility and Development 34(2) 269-269 https://doi.org/10.1071/RDv34n2Ab66
Published: 7 December 2021
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
In vitro embryo production (IVP) is an important tool for genetic improvement in small ruminants. For the success of IVP, semen quality is one of the most important aspects to consider. The differences between ejaculates from the same animal (especially during different seasons) is well documented in domestic sheep (Ovis aries). The objective of this research was to compare the effect of the frozen-thawed semen processed in the breeding season (BS) and nonbreeding season (NBS) on ovine IVP. The research was carried out in the reproduction laboratory at the Palominos Ranch (Jalisco, México). The IVP was performed with a continuous in vitro culture system. Ovaries (n = 196) were collected from a slaughterhouse (León, México) and transported (37°C) to the laboratory within 2 h in physiological saline solution (0.9% NaCl) supplemented with penicillin G (100 IU mL−1) and streptomycin sulfate (100 µg mL−1). For IVP, IVF-Bioscience™ media were used for IVM, IVF, and in vitro culture (IVC). For the IVM, cumulus-oocyte complexes (COCs) were selected (only grades 1 and 2) and matured for 24 h at 38.5°C in 5% CO2 in air and 100% humidity. For IVF, semen from the same ram (Dorper breed) was frozen usinTriladyl™ (Minitube) in both BS and NBS. Semen was adapted to glycerol at 4°C for 2 h and frozen in liquid nitrogen (LN) vapour (5 cm above LN level) for 15 min; at the end of this period, the straws were plunged directly into LN. Matured oocytes (n = 1000) were divided into two groups (500 each, in five replicates) and fertilised in vitro using semen collected either in the BS (frozen in October) or NBS (frozen in May). Both semen samples (BS and NBS) were adjusted at a concentration of 2 × 106 spermatozoa mL−1 and placed with oocytes for 18 h in 38.5°C, 5% CO2 in air, and 100% humidity. The presumptive zygotes were denuded by pipetting and placed in IVC until Day 7 at 38.5°C, 5% CO2, 5% O2, and 90% N2 at 100% humidity. Statistical analysis was carried out with the ANOVA procedure of the Jamovi software (version 1.2; The Jamovi Project) to evaluate percentages of cleaved embryos, embryos with more than six cells, and blastocysts on Day 7 of culture, based on the initial number of oocytes entering IVM. Rates of cleavage, embryos with more than six cells, and blastocysts on Day 7 were similar (P > 0.05) for the BS and NBS groups, respectively: 66.2 ± 6.87%, 60 ± 3.74%, and 55.8 ± 8.2%; 52.6% ± 5.37, 45 ± 9.85%, and35 ± 4.36%. Although BS semen resulted in a numerically higher percentage of blastocysts than NBS semen, this difference was not significant (P = 0.07). In conclusion, under the conditions of this research, the use of either BS or NBS semen had similar results for ovine IVP.
