| dc.description.abstract | Maternal nutrition throughout gestation affects fetal growth and development. The fetal adaptation to conditions in the uterine environment is called fetal programming. These adaptations lead to responsive and adaptive changes in key metabolic organs, such as the jejunum and liver, with effects that persist into adulthood. Although required in small concentrations, vitamins and minerals are essential for physiological, catalytic, and regulatory functions. Cumulative evidence supports their role in fetal programming, influencing performance and health. However, vitamin and mineral supplementation strategies are largely variable among beef producers. The working
hypothesis of this dissertation is that maternal vitamin and mineral supplementation throughout gestation would differentially program the jejunal mucosa and liver through changes in the expression of transcription factors and regulatory gene networks involved with immune response, nutrient uptake, and energy metabolism. Therefore, this work aimed to investigate gene regulatory relationships in the neonatal jejunal mucosa and liver to shed light on potential mechanisms by which maternal vitamin and mineral supplementation during gestation influence developmental programming in heifer calves. To this end, jejunal mucosa and liver gene expression was measured with RNA-Seq in newborn calves collected 30 h after birth from dams fed a diet initiated 60 days pre-breeding. Dams were assigned to either a basal diet (CON; n = 7) or the basal diet plus 113 g•heifer-1•d-1 of vitamin and mineral supplement (VTM; n = 7). No effects were identified in calf morphometrics and organ mass between treatment groups. However, we identified 528 differentially expressed genes in the jejunal mucosa and 630 in the liver between treatment groups. We retrieved 98 and 57 regulatory transcription factors (TFs) in the jejunum and liver through regulatory impact factor analysis, respectively. Over-represented pathways and gene ontology terms in the jejunal mucosa included nutrient transport, lipid metabolism, and immune-related processes. From the liver, significant genes were underlying pathways, such as oxidative phosphorylation, AMPK, PI3K/Akt, and FoxO, which are major regulators of energy homeostasis. In the liver, the maternal diet affected gene connectivity, suggesting a regulatory rewiring of TFs and histone deacetylating genes involved in transcriptional modulation. Our results show that maternal vitamin and mineral supplementation throughout gestation was associated with molecular changes in the neonatal via transcriptomic responses. However, further research is needed to explore whether epigenetic marks are established at birth, persist throughout postnatal development, and potentially contribute to long-term phenotypic outcomes and transgenerational inheritance. | en_US |
