131 DNA methylation profile in bovine fetal liver is affected by maternal vitamin and mineral supplementation during early gestation

Abstract

Abstract Early gestation is the critical period for successful pregnancy establishment. During this period, maternal nutrition affects fetal development with potentially long-lasting consequences on offspring performance. Despite the known effects of vitamins and minerals on embryonic development, supplementation is still not a widely adopted practice. Here we focused on the effects of maternal vitamin and mineral supplementation from pre-breeding to d 83 of gestation. We hypothesized that the DNA methylation pattern of genes involved with fetal hepatic metabolism and function would be altered in response to vitamin and mineral supplementation during early gestation. Sixteen Angus crossbred heifers (~16 mo of age) were randomly assigned to either a treatment (vitamin and mineral supplementation, VTM, n = 8) or control (corn-based carrier without supplementation, NoVTM, n = 8) group. Supplemented heifers received 0.45 kg •heifer-1•d-1 of to provide 113 g of vitamin-mineral premix (Purina Wind & Rain Storm All-Season 7.5 Complete, Land O’Lakes, Inc., Arden Hills, MN) from d 71 to 148 before breeding to d 83 of gestation. All heifers received 100% of NRC recommended nutritional requirements targeting 0.28 kg •heifer-1•d-1 of gain. The heifers were bred through artificial insemination following a 7-d Co-Synch + CIDR estrus synchronization protocol. All pregnant heifers were surgically ovariohysterectomized on d 83, and liver samples were collected from the fetuses. DNA methylation profiles from 16 fetuses (8 per treatment) were determined using Reduced Representation Bisulfite Sequencing (RRBS). The analysis was conducted using methylKit pipeline where data was normalized using principal components. We identified 794 differentially methylated cytosines (DMCs) for the control (NoVTM) vs VTM comparison. Most of the DMCs were found in introns followed by intergenic, promoter, and exonic regions. Among these DMCs, 60% (479) were hypermethylated and 40% (315) were hypomethylated, potentially regulating 739 nearby genes (FDR < 0.1). Biological processes over-represented by these genes included transport of ions through voltage gated channels (KCNK13, KCNT1, CACNA1B, KCNK9, LRRC55, KCNAB2, CACNA1S, KCNJ2, CACNG5, CLIC5, TPCN2, KCNQ1), which may be associated to pregnancy establishment by inducing pregnancy-associated relaxation and uterine artery dilatation. Some genes associated with structural development were also regulated by VTM supplementation (i.e., TIAM1, COL18A1, DYSF, BMP10, RXRA, EHMT1, COL4A2, PLEC, ZFAT, MTMR2, NAV1, ANHX, ACACB, and LIMK2). Collectively, these results suggest that periconceptual maternal vitamin and mineral supplementation affects the methylation pattern and potentially regulates the expression of genes involved in fetal liver development and ion transport.