Impact of mycotoxins of agricultural relevance on reproductive cell biology in cattle

Sustainable animal production is critical to achieve food security for the rapid population growth predicted for this century. As such, the demand for animal protein will continue to rise, with the dairy sector providing key nutrients for human consumption. Mycotoxins are toxic metabolites produced by fungi that represent a major challenge for sustainable animal production worldwide. In dairy cattle herds, mycotoxins such as deoxynivalenol (DON) and zearalenone (ZEN) are highly prevalent in feedstuffs, but clinical presentation of mycotoxicosis is not observed due to the low level of exposure. Hence, their potential impact on cattle reproductive performance is unknown. The capability to produce a calf has a direct impact on the ability of the cow to produce milk and in turn on farm profitability. Hence, efficient reproductive performance is pivotal for sustainable dairy production and it is impaired by early embryonic death, accounting for loss of 40% of pregnancies, with evidence highlighting occurrence of embryonic losses in the first week of pregnancy in cattle (i.e. during preimplantation embryo development, when the bovine embryo reaches the blastocyst stage with around 150 cells). In vitro studies in pigs showed that DON and ZEN can impair oocyte (egg) development competence (i.e. the capacity of an oocyte to develop into a preimplantation embryo), but their effects on the developmental competence of bovine oocytes is virtually unknown. This project therefore aims to generate novel mechanistic knowledge on the impact of DON and ZEN on bovine oocyte developmental competence using physiologically relevant values using concentrations representative of real-life exposure. Cellular and molecular endpoints will be analysed in an in vitro bovine model of preimplantation embryo production. The project will use an in vitro model with oocytes extracted from cattle ovaries collected from a commercial abattoir. The ovaries are a by-product of the cattle industry; hence, no animal will be killed for the sake of this project. The project would allow for the mechanisms of action of mycotoxins to be determined, generating opportunities for future therapeutic development to prevent early pregnancy loss, and hence improving animal welfare and profitability for farmers (i.e. the SAF focus areas 'sustainable agricultural systems' and 'crop and farmed animal health'). The relevance of this research is further highlighted by prediction models indicating an increase in mycotoxin crop contamination as a consequence of climate change.