Abstract / Summary
Intrauterine growth restriction (IUGR) has a negative impact on reproductive performance in domestic animals. In this study, we attempt to explore the etiology of IUGR in sows and test the potential beneficial effects and underlying molecular mechanisms of melatonin on IUGR. The results indicated that there was a negative correlation between the concentration of melatonin in the peripheral blood of pregnant sows and the ratio of IUGR, and the concentration of melatonin in the umbilical cord blood of IUGR piglets was abnormally decreased. Supplementing sows with an appropriate dose of melatonin can increase the average birth weight of piglets and reduce the proportion of IUGR piglets. Reduced representation bisulfite sequencing revealed a direct association between abnormal DNA methylation in the placenta of sows and IUGR piglets. The increased DNA methylations of key genes responsible for placenta functions downregulated their expressions. Gene downregulation caused placenta dysfunction and IUGR. Melatonin significantly reduced DNA methylation of genes related to placental function. We identified that melatonin supplementation during mid-gestation stages specifically targeted the CGI, CGI shore, exon, intron, and 3′ untranslated regions of placental genes. The results provide novel information to target the high incidence of IUGR in pigs as well as other species.