216 Effect of removing hormone and antioxidant supplementation during oocyte maturation in cattle: preliminary results
L. A. G. Martinhão A E , L. P. Martins A , D. N. Ribas D E , J. G. V. de Grázia B E and J. H. M. Viana A CA Universidade de Brasília, Brasília, Distrito Federal, Brasil
B FIVX Apoyar Biotech, Juiz de Fora, Minas Gerais, Brasil
C Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brasil
D Universidade do Estado de Mato Grosso, Alta Floresta, Mato Grosso, Brasil
E Norte Embryo, Alta Floresta, Mato Grosso, Brasil
Reproduction, Fertility and Development 35(2) 237-237 https://doi.org/10.1071/RDv35n2Ab216
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Research focusing on the development of gamete and embryo culture systems was generally based on the supplementation of media used in vitro. Recently, however, questions have been raised about whether the excess of substances during embryo culture could have possible long-term consequences for animal health and disease. In this study, we evaluated the effect of removing hormones (FSH, LH, insulin, and oestradiol) and antioxidants (β-Mercaptoethanol) from the medium used for in vitro maturation of oocytes. Cumulus-oocyte complexes (COC) recovered from slaughterhouse ovaries (mostly from Nelore [Bos taurus indicus] cows) were transported in saline (38°C) to an in vitro embryo production (IVEP) laboratory (Norte Embryo) located at Alta Floresta, MT, Brazil. COC with more than three layers of cumulus cells and dark and homogeneous cytoplasm, morphologically classified as grade I (n = 1,095), were randomly allocated into three groups, which underwent in vitro maturation (IVM) in TCM199 as follows: G1, control group, supplemented with FSH, LH, insulin, oestradiol, and β-Mercaptoethanol (n = 360); G2, without hormone supplementation (n = 360); and G3, without hormone and antioxidant supplementation (n = 375). Cumulus cells’ expansion was evaluated at 22 h of IVM and subjectively scored as good, fair, or poor. The COC from all groups were then in vitro fertilised with semen from Abeerden Angus sires with known fertility and presumptive zygotes were in vitro cultured under the same medium and incubation conditions. Data were analysed using the Proc Glimmix or the Proc NPar of the SAS (SAS Institute). As expected, the lack of hormone supplementation resulted in lower COC expansion in G2 and G3, compared with G1 (P < 0.0001). However, no differences (P > 0.05) were observed among G1, G2, and G3 on cleavage rate (73.5 ± 1.2, 73.7 ± 1.2 and 67.1 ± 1.3, respectively), blastocyst rate at Day 6 (27.6 ± 0.5, 23.6 ± 0.6 and 23.6 ± 0.7), blastocyst rate at Day 7 (37.9 ± 0.7, 37.7 ± 1.0 and 32.6 ± 0.9), or on the percentage of hatched blastocysts at Day 10 (79.9 ± 0.7, 77.1 ± 0.7 and 74.4 ± 0.8). Our preliminary data suggest that removal of hormone supplementation from IVM media, in the conditions used in the current experiment, does not significantly impact IVEP. However, potential impacts on embryo quality and developmental potential still need to be investigated.
