Effects of in vitro maturation medium supplemented with melatonin on the development and gene expression of deoxynivalenol-exposed porcine oocytes.

Deoxynivalenol (DON) is one of the most prevalent mycotoxins found in livestock feed and is known to impair reproductive physiology and oocyte quality. Melatonin (MEL), a potent antioxidant, has been reported to mitigate DON-induced cytotoxicity during in vitro maturation (IVM) of porcine oocytes and cumulus cells. This study aimed to evaluate the impact of DON and MEL supplementation during IVM on oocyte developmental competence and transcriptomic profiles. Developmental outcomes revealed that exposure to DON (1 μM) significantly reduced oocyte maturation (47.6%), whereas co-treatment with DON (1 μM) plus MEL (1 μM) markedly improved the maturation rate (74.4%). To investigate underlying molecular changes, next-generation sequencing (NGS) was performed, followed by quantitative PCR (qPCR) validation of 14 candidate genes. In cumulus cells, MEL supplementation significantly upregulated ATP5F1E, TCEAL2, and RNase P compared to DON treatment alone. In oocytes, MEL restored the expression of mitochondrial and stress-related genes, including NDUFB6, ATP8, and SEC61A2, while reducing the expression of COX15, ACSL4, CPEB2, and MAP7 genes associated with mitochondrial clearance, ferroptosis, and cytoskeletal stress. These expressions were consistent between NGS and qPCR analyses. Collectively, the results suggest that MEL supplementation during IVM alleviates DON-induced cytotoxicity by enhancing mitochondrial function, reducing oxidative stress, and normalizing gene expression in porcine oocytes and cumulus cells. Moreover, these findings support MEL's potential as a protective agent in mycotoxin-contaminated reproductive systems.