Poirier, Mikhaël: Effect of cow’s metabolic status on the epigenome profile of oocytes and embryos. - Bonn, 2020. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-56938
@phdthesis{handle:20.500.11811/8168,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-56938,
author = {{Mikhaël Poirier}},
title = {Effect of cow’s metabolic status on the epigenome profile of oocytes and embryos},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2020,
month = jan,

volume = 195,
note = {In lactating cows, intensive genetic selection for improved milk production has been associated with reduced reproductive capacity, leading to increased early embryo loss. During post-calving lactation, the cow’s dietary intake is outmatched by the energy needed for biological processes causing the cow to enter a state of negative energy balance, associated with a perturbed metabolism. This thesis project aimed to investigate the impact of this transient metabolic stress on the epigenetic profile of genes involved in developmental competency of gametes and embryos in lactating cows. To do so, oocytes were collected during early and mid postpartum period from metabolically profiled multiparous cows as well from nulliparous heifers. Comparatively, in vitro derived early cleaving embryos were cultured in vivo in lactating cows as well as heifers to morula stage and collected through uterine flushing. Epigenetic profile of both samples was assessed by whole genome bisulfite sequencing.
Metabolic profiling revealed that selected lactating cows exhibited significantly higher levels of non-esterified fatty acids and beta-hydroxybutyrate during early post-partum and embryo transfer than nulliparous heifers. Accordingly, genome-wide hypomethylation of early post-partum oocytes was observed, and mid postpartum oocytes genomic feature methylation was similar to heifer’s oocytes. Inversely, embryos from lactating cows were generally hypermethylated when compared to heifers. Further methylation profiling of early postpartum oocytes revealed 32,990 differentially methylated regions in early postpartum oocytes overlapping genes involved in metabolic pathways, carbon and fatty acid metabolism. Similarly, embryos grown in lactating cows revealed 13,383 differentially methylated regions in genes involved in metabolic and fatty acid biological processes, as well as trophoblast invasion and embryo implantation. Both oocytes and embryos collected from metabolically stressed animals revealed differentially methylated regions of genes involved in lipid metabolic processes, and imprinted genes putatively acquired during maturation that must be maintained during embryo development.
Taken together, these studies demonstrate that transient metabolic stress associated with early lactation influences epigenetic status of oocytes and embryos of genes involved in developmental competency. Genes found in signaling pathways provide novel candidates for effector supplementation of these signaling molecules both during oocyte maturation and embryo culture to ultimately improve reproductive processes in lactating cows.},

url = {http://hdl.handle.net/20.500.11811/8168}
}

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