(PTFS01-05-24) One-Carbon Metabolite Supplementation Influences Fetal Liver Metabolites and Metabolic Pathways in a Diet-Dependent Manner During Early Pregnancy in Heifers

Objectives: The study investigated the effects of nutrient restriction and one-carbon metabolite (OCM) supplementation on fetal liver metabolomics in pregnant beef heifers, focusing on amino acid, cofactors and vitamins, carbohydrate, and energy metabolism at day 63 of gestation.

Methods: Thirty-one cross-bred Angus heifers were artificially inseminated and divided into four nutritional groups in a 2 × 2 factorial design. The first factor was gain, which included control diet (CON; 0.45 kg/day ADG) versus restricted diet (RES; -0.23 kg/day). The second factor was OCM: supplementation (+OCM; methionine [7.4 g/day] and ruminal protected choline [44.4 g/day] in a ground corn carrier, and injections of 20 mg vitamin B₁₂ and 320 mg folate weekly) or no supplementation (-OCM; injection of saline and corn carrier). Metabolomic analysis of fetal liver tissues collected at 63 days of gestation was conducted using ultrahigh-performance liquid chromatography–tandem mass spectroscopy. Statistical analyses included Two-Way ANOVA and Welch’s two-sample T-tests, with pathway enrichment analyzed using MetaboLync and MetaboAnalyst 5.0.

Results: About 23% of the metabolites in the fetal liver were influenced by either dietary gain, OCM supplementation, or their interaction. Most of these metabolites were found in greater concentrations in the CON versus RES, particularly in pathways related to lysine metabolism, leucine, isoleucine and valine metabolism, and tryptophan metabolism; however, specific pathways including glutamate, histidine, methionine, and tocopherol metabolism saw an increase in metabolite levels in RES compared to CON (P ≤ 0.05). Moreover, OCM supplementation resulted in a greater abundance of metabolites (P ≤ 0.05), affecting pathways associated with lysine, methionine, guanidino and acetamido, and nicotinate and nicotinamide metabolism. Notably, OCM supplementation with moderate rate of gain significantly increased concentrations of ophthalmate, N-acetylglucosamine, ascorbic acid 3-sulfate, and 3-methylglutarylcarnitine.

Conclusions: The nutritional treatments appear to influence fetal metabolism and provide insights into the impact of maternal nutrition on the development of the fetal liver metabolism during early gestation.

Funding Sources: Supported by the USDA, which is an equal opportunity employer.