In the pig breeding industry, the transfer of fertilized eggs, so-called embryo transfer, can contribute to more sustainable meat production through faster progress in breeding programmes, in addition to increased biosecurity and animal welfare.
But there is a big challenge in achieving this.
The application of embryo transfer in swine is limited by embryo production and storage, as non-optimal in vitro culture conditions affect embryo development and quality, and pig embryos are highly sensitive to freezing because of their high fat content.
"Non-optimal in vitro culture conditions affect embryo development and quality," writes Linda Marijke to inn.no. She has completed her doctoral research in the PhD programme Applied Ecology and Biotechnology.
An aim of this thesis, which has been created in collaboration between INN University and Norsvin, was to study the storage of in vitro produced pig embryos in order to achieve good survival after transport to the location where transfer to the female animal is to take place.
"An associated aim was identifying new oocyte quality markers, potentially aiding optimization of oocyte maturation, and thereby in vitro embryo production", says Haug.
In their natural state, egg cells are surrounded by so-called cumulus cells, which are essential for the development and maturation of the egg cells.
"This study investigated whether activity of genes (gene expression) in cumulus cells could be markers of oocyte quality and found four genes associated with metabolism as potential oocyte quality markers. Gene expression in cumulus cells could be more suitable markers than gene expression in oocytes", according to the researcher.
Here you'll find more information about Linda Marijke Dekker Haug's public defence on 18 March 2024.
The main findings of the PhD:
- Pig embryos can be stored for three hours in CO2-free medium at 37 °C without compromising embryo quality.
- Faster developing embryos are more suitable for storage than slower developing embryos.
- Expression of four genes associated to metabolism (CPT2, BBOX1, G6PD and ALDOA) in cumulus cells were identified as potential markers of oocyte quality in pigs.
- Gene expression in cumulus cells appeared to be more suitable markers of oocyte quality than gene expression in the oocytes.
- Cumulus cells and oocytes in pigs seem to be able to regulate the expression of genes involved in L-carnitine synthesis, an important enzyme for fatty acid metabolism.
- The combined use of the two genes ACTB and PFKP was identified as the optimal normalization of gene expression data from pig oocytes.
- The expression of epigenetic related genes in oocytes, essential for embryo development, showed potential as oocyte quality markers.
Contact information:
- linda.haug@inn.no
- Phone
- +47 62 43 07 77