Dietary sodium sulphate supplementation during mid-to-late gestation improves placental angiogenesis, bile acid metabolism, and serum amino acid concentrations of sows

Sulphate plays a vital role in the growth and development of the foetus. Sodium sulphate (Na₂SO₄) is utilised as a dietary protein nutrient factor and helps replenish sulphur elements in livestock and poultry. Therefore, this study aimed to investigate the effects of Na₂SO₄ supplementation in mid to late pregnancy on bile acid metabolism, amino acid metabolism, placental vascular development and antioxidant capacity of sows. At day 1 of gestation (G1), a total of twenty-six primiparous sows were carefully chosen and randomised into two groups: (1) control group, (2) Na₂SO₄ group (1.40 g/kg). Blood samples and placentas from sows were collected to measure biochemistry parameters, antioxidant indexes, placental vascular density, and indicators related to bile acid metabolism and amino acid concentrations, respectively. We found that dietary supplementation with Na₂SO₄ had a tendency for a reduction of incidence of stillborn at farrowing. Further observation showed that sows supplemented with Na₂SO₄ had decreased total bile acid level in cord blood, and increased placental gene expression of sulphotransferase and organic anion transport peptide. Na₂SO₄ supplementation increased catalase and total superoxide dismutase activity in cord blood, decreased placental malondialdehyde content, and enhanced placental protein expression of Sirtuin 1. Moreover, Na₂SO₄ consumption resulted in increased vascular density of placental stroma and elevated amino acid levels in sows and cord blood. Furthermore, maternal Na₂SO₄ consumption reduced serum urea concentrations of sows and umbilical cord blood at G114. In addition, dietary supplementation with Na₂SO₄ activated the protein expression of the placental mechanistic target of rapamycin complex 1. Collectively, these findings indicated that maternal supplementation with Na₂SO₄ during mid-to-late gestation elevated foetal survival via improving placental angiogenesis, bile acid metabolism and amino acid utilisation.