Abstract

Fumonisin B 1 (FB 1 ), as the most toxic fumonisin , is a common Fusarium mycotoxin contaminant of feed stuff and food, posing a potential health hazard to animals and humans. FB 1 has been reported to cause hepatotoxicity , neurotoxicity , nephrotoxicity , immunotoxicity and embryotoxicity ; however, little information is available on whether FB 1 has toxic effects on mammalian oocytes . Herein, we adopted porcine oocytes as models to explore the effects and potential mechanisms of FB 1 on mammalian oocytes during in vitro maturation. Porcine cumulus oocyte complexes (COCs) were exposed to 0, 20, 30 and 40 μM FB 1 for 44 h during in vitro maturation, and the results reported that first polar body (PB1) extrusion was significantly inhibited when the FB 1 concentration reached 30 ( P  < 0.01) or 40 μM ( P  < 0.001). Further cell cycle analysis revealed that meiotic progression was disrupted, with a larger proportion of the 30 μM FB 1 -treated oocytes being arrested at the germinal vesicle breakdown (GVBD) stage ( P  < 0.01). After being treated with 30 μM FB 1 for 28 h, the percentage of oocytes with aberrant spindle assembly was observably increased ( P  < 0.01), and the distribution of actin filaments on the plasma membrane was significantly reduced ( P  < 0.05). Furthermore, an observably higher rate of abnormal mitochondrial distribution ( P  < 0.05) and significantly decreased mitochondrial membrane potential (MMP) ( P  < 0.05) were observed in FB 1 -exposed oocytes. In addition, ROS generation in FB 1 -treated oocytes was rapidly increased ( P  < 0.05), while the transcriptional levels of antioxidant-related genes ( CAT, SOD2 and GSH-Px ) were sharply decreased compared with those in the control group. Additionally, the incidence of early apoptosis in FB 1 -treated oocytes was also significantly increased ( P  < 0.05), suggesting that FB 1 exposure induced oxidative stress and further triggered apoptosis in porcine oocyte