FFTC Deputy Director and livestock expert Dr. Takashi Nagai recently attended the 41st annual meeting of the International Embryo Transfer Society (IETS) at the Palais des Congrès de Versailles in France, where he said the most advanced and updated technologies related to embryo transfer were presented and discussed. The former Director of the Animal Breeding and Reproduction Division of the Institute of Livestock and Grassland Science of the National Agriculture and Food Research Organization in Japan presented a poster and attended the Past Presidents’ breakfast and discussed the future direction of IETS with many of its past presidents.
FFTC Deputy Director Dr. Takashi Nagai with Dr. Kazuhiro Kikuchi, Senior Researcher of the National Institute of Agrobiological Sciences (NIAS), Japan during the 41st IES Meeting
Below is a summary of Dr. Nagai’s report:
There were more than 600 participants from all over the world who attended the 41st annual meeting of IETS. The main theme of the meeting was “Reproductive Performance: At the Crossroads of Genetics and the Environment”, and there were two pre-conferences, five main plenary sessions, poster session and five concurrent sessions. I presented posters and attended the Past Presidents’ Breakfast. The first plenary session entitled “From Genotype to Phenotype” was outstanding because it clearly showed that genetic tools have become so advanced that effects of environment such as feeding on genetics of animals can be elucidated at the molecular level. There were 362 posters presented and they were categorized according to sections as shown in Table 1. The section of Oocyte Maturation has the highest number of posters followed by IVF/IVP (In virto fertilization/In vitro production), Gene Expression and Cryoprservation/Cryobiology. Recently it has been reported that establishment of efficient in vitro oocyte maturation is a key to increase quantity and quality of in vitro produced embryos for embryo transfer; this fact is confirmed by the highest number of papers in Section of Oocyte Maturation.
The following papers were presented by me or my coauthors as posters at the meeting. Furthermore, “Genome-wide analysis of DNA methylation in two different breeds” was selected to be presented at the main symposium as an oral presentation.
1) Genome-wide analysis of DNA methylation in two different breeds: Holstein and Japanese Black. The aim of this study was to assess to which extent the methylome of two specialized cattle breeds – the dairy breed Holstein and the beef breed Japanese Black - could show some variabilities. The Differentially Methylated Regions were significantly enriched in genes involved in placental development and lactation, suggesting an adaptation of the dairy breed Holstein and the beef breed Japanese Black to the different metabolic demand during gestation.
2) The effects of collection season and storage duration in liquid nitrogen on post-warming survival and nuclear maturation of immature porcine oocytes preserved by solid surface vitrification. The effects of collection season and storage duration of vitrified porcine oocytes in liquid nitrogen (LN2) on their survival and maturation ability after warming were investigated. It was found that that the oocyte collection season affects survival of vitrified oocytes whereas storage duration in LN2 does not affect this parameter. Furthermore, nuclear maturation of oocytes that survive after vitrification and warming is not affected by their collection season and storage length.
3) Comparison of sugars, combinations of permeable cryoprotectants and equilibration regimens for the solid surface vitrification of immature porcine oocytes. Cryotop and solid surface vitrification (SSV) are frequently used methods for the cryopreservation of porcine oocytes. These methods differ not only in the vitrification carrier but also in the cryoprotectant (CPA) treatment including the type of sugar, permeable CPA (pCPA) combinations, and the equilibration regimen. This study compared the distinct points of CPA treatment of these two methods in order to determine the optimum CPA treatment for the SSV of immature porcine oocytes. It was found that trehalose and sucrose are equally effective supplements during vitrification and warming.
4) The effects of bulls and X-sorting of sperm on the accuracy of noninvasive criteria to predict blastocyst formation of in vitro-produced bovine embryos. The aim of this study was to investigate the effects of bulls and X-sorting of sperm on the accuracy of the simple non-invasive criteria, such as a normal cleavage pattern defined by even blastomeres without fragments or protrusions, to predict the competence of bovine IVF embryos to develop to the blastocyst stage in vitro. It was found that a first cleavage within 28 h after IVF to 2 even blastomeres without fragments or protrusions are accurately predictive criteria for the developmental competence of bovine embryos to the blastocyst stage regardless of bulls and sperm sorting.
Dr. Nagai also participated in meeting’s main symposium where he and his colleagues made an oral presentation
The Palais des Congrès de Versailles, France was the venue of the 41st IES Meeting