In vitro maturation of bovine and porcine oocytes as a versatile model for toxicity and metabolism studies

Abstract Assisted reproductive technologies (ARTs) have significantly advanced, yet the definition and assessment of oocyte quality remain pivotal for successful embryo development. Oocyte quality is influenced by various factors, including lifestyle, age, metabolic status, and exposure to pollutants or medications. Non-invasive techniques to evaluate oocyte quality are limited, and invasive methods are commonly used in research. In vitro maturation (IVM) of oocytes from cows and pigs offers valuable models for human ART due to various similarities, though there are species-specific differences. These IVM and in vitro embryo production (IVEP) systems offer valuable insights into oocyte maturation and early embryo development without use of experimental animals. While bovine IVEP is well established, porcine IVEP has great potential for improvement. The models can be crucial for reproductive biology and biomedical research and can contribute to advancements in areas such as human fertility treatments and toxicity testing. Apart from oocyte quality assessment, there are challenges, such as variability in oocyte quality from slaughterhouse ovaries and the difficulty in mimicking the complex in vivo environment. Emerging technologies, like gene-expression analysis tools, and non-invasive -omics approaches hold promise for overcoming some obstacles by improving precision, sensitivity, and reproducibility in IVEP studies. In this review, we discuss the model in simulating various conditions but with main focus on metabolic challenges and in toxicity screening and aim to give an overview of the current and possible future use of IVM in cows and pigs as a model for the same or other mammalian species, as well as the limitations.