Impact of Maternal Omega-3 Fatty Acid Intake on Ovine Placental and Fetal Tissue Metabolism

OBJECTIVES: Dietary supplementation of omega-3 fatty acids such as docosahexaenoic acid (DHA) during pregnancy is often recommended to support optimal fetal brain development and cognitive function of the offspring. DHA supplementation also influences cardiometabolic risk parameters in adults, but its effect on fetal metabolism and subsequent risk is poorly understood. The aim of this study was to determine the effects of maternal DHA supplementation (MDS) on placental and fetal nutrient handling during pregnancy. METHODS: White-faced ewes were fed either a control diet (Show-rite NewCo Lamb Feed) or a DHA-supplemented diet (control diet + 3% w/w algae-derived DHA) from 2–3 weeks before pregnancy until mid-gestation (75 days), after which a C-section was performed to collect the placenta and fetal tissues for metabolic analyses. RESULTS: MDS significantly increased serum DHA levels and decreased serum triglycerides in the uterine (maternal) circulation, but not umbilical (fetal) circulation. Nevertheless, MDS resulted in significant DHA enrichment of the placenta and all fetal tissues examined, and differentially affected the protein expression of the four major fatty acid transport proteins FATP1, FATP4, CD36 and FABP in placenta, muscle, liver and heart, but had no effect on kidney or brain. Consistent with these findings, MDS tended to increase the capacity for fat over pyruvate oxidation in fetal muscle and heart, but favored a greater capacity for glucose uptake and oxidation in fetal liver. CONCLUSIONS: This study is the first to validate use of an ovine model for investigating the impact of maternal DHA supplementation on fetal metabolism and development. Results demonstrate a complex tissue-specific effect of MDS on fetal tissue carbohydrate and fatty acid metabolism that favors a greater capacity for serum glucose disposal and fatty acid oxidation. Whether these changes ultimately impact nutrient metabolism and cardiometabolic risk in the offspring later in life merits further investigation. FUNDING SOURCES: Colorado Agricultural Experiment Station.