Melatonin supplementation alters maternal and fetal amino acid concentrations and placental nutrient transporters in a nutrient restriction bovine model

Authors: SWANSON, REBECCA - Mississippi State University; CONTRERAS-CORREA, ZULLY - Mississippi State University; DINH, THU - Mississippi State University; KING, HEATH - Mississippi State University; SIDELINGER, DARCIE - Mississippi State University; BURNETT, DERRIS - Mississippi State University; LEMLEY, CALEB - Mississippi State University

Submitted to: Metabolites
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2022
Publication Date: 12/2/2022
Citation: Swanson, R., Contreras-Correa, Z.E., Dinh, T., King, H., Sidelinger, D., Burnett, D.D., Lemley, C.O. 2022. Melatonin supplementation alters maternal and fetal amino acid concentrations and placental nutrient transporters in a nutrient restriction bovine model. Metabolites. 12:1208. https://doi.org/10.3390/metabo12121208.
DOI: https://doi.org/10.3390/metabo12121208

Interpretive Summary: Compromised pregnancies are characterized by placental insufficiency resulting in poor fetal growth and development, and increased morbidity and mortality postnatally. Placental insufficiency is caused by decreased uterine blood flow, nutrient transport, and placental size, resulting in intrauterine growth restricted (IUGR) offspring. Previous research has shown that melatonin increases antioxidant capacity in dairy cows. Additionally, melatonin has vasodilative and vasoconstrictive properties that may regulate and redistribute blood flow. Overall, this study implies melatonin is an effective therapeutic for amino acid and nutrient transporter alterations caused by nutrient restriction, however, more so during the summer months. Livestock models of developmental programming lack consideration of season and the respective environmental changes, which has been proven to impact amino acids and fetal growth in bovine, which are not seasonal breeders. The fall season may be more detrimental to placental efficiency compared to the summer season, suggesting a need for research into the seasonal effects of bovine pregnancy, including therapeutics, and management strategies.

Technical Abstract: Melatonin rescues uterine blood flow and fetal body weight in a seasonal dependent manner within a nutrient restriction bovine model. We sought to identify the effects of nutrient restriction, melatonin, and sampling time on maternal and fetal amino acids, and placental nutrient transporters. Pregnant heifers received adequate or restricted nutrition, and 20 mg of melatonin or placebo from gestational days 160–240 over two seasons. On day 240 maternal and fetal blood, amnion, and placentomes were collected. Amino acid concentrations were determined by gas chromatography-mass spectrometry. Caruncle and cotyledon tissues were assessed for nutrient transporter density by qPCR. Data were analyzed using the MIXED procedure of SAS for fixed effects. In fall, melatonin rescued effects of nutrient restriction on System N, Anion, and total maternal amino acids. Furthermore, melatonin rescued effects of nutrient restriction on Systems A, N, Br, Bo, and essential amnion amino acids. In summer, melatonin rescued effects of nutrient restriction in Systems Br and Bo maternal amino acids. Furthermore, melatonin rescued effects of nutrient restriction on caruncle SLC38A10 and SLC38A2. Melatonin rescued effects of nutrient restriction in a seasonal dependent manner. These data align with previous studies suggesting melatonin is a more effective therapeutic in summer months.