Parameters to identify good quality oocytes and embryos in cattle

Abstract

Oocyte/embryo selection methodologies are either invasive or noninvasive and can be applied at various stages of development from the oocyte to cleaved embryos and up to the blastocyst stage. Morphology and the proportion of embryos developing to the blastocyst stage are important criteria to assess developmental competence. Evaluation of morphology remains the method of choice for selecting viable oocytes for IVP or embryos prior to transfer. Although non-invasive approaches are improving, invasive ones have been extremely helpful in finding candidate genes to determine oocyte/embryo quality. There is still a strong need for further refinement of existing oocyte and embryo selection methods and quality parameters. The development of novel, robust and non-invasive procedures will ensure that only embryos with the highest developmental potential are chosen for transfer. In the present review, various methods for assessing the quality of oocytes and preimplantation embryos, particularly in cattle, are considered. These methods include assessment of morphology including different staining procedures, transcriptomic and proteomic analyses, metabolic profiling, as well as the use of artificial intelligence technologies.

Application of imaging and spectroscopy techniques for grading of bovine embryos - a review

“…In the current manual grading of bovine embryos, only qualitative morphological features are used for decision making. However, while using image based grading systems, additional data such as proteomics, metabolomic profile, quantitative or constructed morphological features can be incorporated to obtain beneficial information about embryos ( 36 ). Researchers are currently in pursuit of developing an accurate, repeatable, and most importantly, objective method of determining the gestational success of bovine embryos post-transfer.…”

“…MCB, monochlorobimane (reduced glutathione); PF1, perfluoxy 1 (hydrogen peroxide) and MTR, Mitotracker Red CMXRos (active mitochondria). proteomics, metabolomic profile, quantitative or constructed morphological features can be incorporated to obtain beneficial information about embryos (36). Researchers are currently in pursuit of developing an accurate, repeatable, and most importantly, objective method of determining the gestational success of bovine embryos post-transfer.…”