84 Actions of DKK1 on the bovine embryo during the morula-to-blastocyst stage of development on pregnancy outcomes and placental hormone secretion after embryo transfer
T. F. Amaral A , J. G. V. Grázia B , A. M. Gonella-Diaza C , L. A. G. Martinhão D , D. Heredia C , G. D. Melo E , K. G. Pohler E , E. Estrada-Cortés A I , S. Dikmen F , F. Sosa A , L. M. Jensen A , L. Sang G , L. G. B. Siqueira H , J. H. M. Viana H and P. J. Hansen AA Department of Animal Sciences, University of Florida, Gainesville, FL, USA
B FIVX Apoyar Biotech LTDA, Juiz de Fora, Minas Gerais, Brazil
C Department of Animal Sciences, University of Florida, North Florida Research and Education Center, Marianna, FL, USA
D Biological Science Institute, University of Brasília, Brasília, DF, Brazil
E Department of Animal Sciences, Texas A&M University, College Station, TX, USA
F Department of Animal Science, Faculty of Veterinary Medicine, Bursa Uludag University, Bursa, Turkey
G Institute of Animal Husbandry and Veterinary Medicine, Fujian Academy of Agricultural Sciences, Fuzhou, China
H Brazilian Agricultural Research Corporation (Embrapa), Juiz de Fora, Minas Gerais, Brazil
I Campo Experimental, Centro Altos de Jalisco CIRPAC-INIFAP, México, Jalisco, Mexico
Reproduction, Fertility and Development 34(2) 279-279 https://doi.org/10.1071/RDv34n2Ab84
Published: 7 December 2021
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Dickkopf-1 (DKK1) is an embryokine expressed in the bovine endometrium that has been reported to act on the bovine embryo between Days 5 and 7 of development to increase the number of trophectoderm cells in the blastocyst and to improve survival after embryo transfer (ET). Three experiments were conducted to further examine effects of DKK1 on embryo survival and circulating concentrations of pregnancy-associated proteins (PAG) and placental lactogen. Beef oocytes retrieved from slaughterhouse ovaries were fertilised with Y-sorted (experiments 1 and 3) or X-sorted (experiment 2) Angus semen. Cultured embryos were treated at Day 5 after fertilisation with either vehicle (V) or 100 ng mL−1 recombinant human DKK1. At Day 7.5, blastocysts were selected and transferred to either beef (Exp 1 and 2) or dairy recipients (Exp 3). Either a single embryo (Exp 1 and 3) or two embryos (Exp 2; both ipsilateral to the corpus luteum) were transferred. Data were analysed by the GLIMMIX and GLM procedures of SAS (SAS Institute Inc.). Treatment did not affect pregnancy rate at Day 30 of gestation, calving rate or pregnancy loss (P > 0.05). Values (V vs. DKK1) for pregnancy rate at Day 30 were 46.2% (24/52) vs. 43.1% (22/51) (Exp 1); 53.3% (16/30) vs. 57.0% (45/79) (Exp 2); and 32.8% (21/64) vs. 26.7% (16/60) (Exp 3). Pregnancy loss from Day 30 to 60 of gestation was 8.3% (2/24) vs. 9.1% (2/22) (Exp 1); 6.3% (1/16) vs. 15.6% (7/45) (Exp 2); and 28.6% (6/21) vs. 18.8% (3/16) (Exp 3). Calving rate was 40.4% (21/52) vs. 37.3% (19/51) (Exp 1) and 23.4% (15/64) vs. 20.0% (12/60) (Exp 3). Cows have not yet calved for Exp 2. For Exp 1, PAG concentrations at Day 160 were lower for V than for DKK1 (12.7 ± 1.6 ng mL−1 vs. 16.3 ± 0.9 ng mL−1; P = 0.051). Treatment did not affect PAG concentration at Day 264 or concentrations of placental lactogen at Days 160 or 264. For Exp 3, there was no effect of treatment on PAG concentration at Day 36 or 64 of gestation. In conclusion, there was no evidence that DKK1 treatment enhances pregnancy outcomes. Effects on PAG concentrations implies that DKK1 causes long-term changes in placental function. Further work will be performed to determine postnatal changes associated with DKK1 treatment.
This research was funded by USDA 2017-67015-26452.
