Does glyphosate affect the in vitro maturation and further development of bovine oocytes?

The aim of this study was to determine, whether glyphosate affects the maturation and further development of bovine oocytes in vitro. The pure active ingredient and a glyphosate-based herbicide were compared in the analyses. For this purpose, glyphosate and the glyphosate-based herbicide were added to the maturation medium in active substance concentrations of 1 mu g/ml and 10 mu g/ml. The maturation, cleavage and development rates of the tested groups showed no statistically significant differences irrespective of the concentrations used. The average ratio of live to dead cells of stained blastocysts also showed no significant differences between groups treated with glyphosate and the controls. The relative expression levels of selected genes were only evaluated for the concentration of 10 mu g/ml. The bone morphogenetic protein 15 (BMP15) and zygote arrest 1 (ZAR1) were significantly higher expressed in oocytes treated with the active ingredient as compared to the control. In cumulus cells, the relative expression of the estrogen receptor 1 (ESR1) was significantly higher after treatment with the active ingredient than in the control. No differences between the effect of glyphosate formulated as a herbicide and glyphosate in pure form were observed.