Effect of In Vitro Copper, Zinc, Manganese, And Selenium Supplementation on Bovine Granulosa Cell Culture

Trace minerals, such as copper (Cu), zinc (Zn), manganese (Mn), and selenium (Se), are essential nutrients that support many biological functions in livestock, including growth, immune health, and reproduction. However, research from the Utah Veterinary Diagnostic Laboratory shows that many cattle in Utah suffer from mineral deficiencies, which could impact their overall health and performance. While much research has focused on supplementing cattle with trace minerals after they are weaned or during the feedlot stage, fewer studies have explored how providing these minerals to reproducing females affects their offspring's health and reproductive potential. This study aims to better understand how these key minerals influence reproductive cells in cattle. This study examined how supplemental Cu, Zn, Mn, and Se influence bovine granulosa cells, which are critical for ovarian function and hormone production. Granulosa cells were isolated from slaughterhouse bovine ovaries and cultured with media containing eight concentrations of each trace mineral to assess their effects on cell survival and growth. After identifying the optimal mineral concentrations, we examined how the cells responded by measuring their oxidative stress levels, hormone production, and gene expression. Our findings revealed that while the granulosa cells could generally tolerate a range of mineral concentrations, the length of time they were cultured had a greater impact on their survival and growth than the mineral concentration itself. Moderate levels of Cu and Zn helped the cells grow faster, but higher concentrations of Zn reduced their long-term survival. Mn and Se had only minor effects, though Mn appeared slightly harmful in some cases. One key discovery was that all four minerals increased oxidative stress in the cells, with Cu and Zn causing the highest levels. However, when all four minerals were combined, the stress was somewhat reduced, suggesting a complex balancing effect. Importantly, Cu, Zn, and Mn increased the production of progesterone, a hormone essential for production, while estradiol, another key hormone, remained mostly unchanged. Gene expression analysis also showed significant differences in cell function and antioxidant activity across the different treatments. Overall, this study highlights the importance of properly balancing trace minerals in cattle diets to support reproductive health. Future research will focus on how these changes influence oocyte development, embryo growth, and overall fertility in cattle.