Triacetin

The survival of early embryos during the first trimester is closely associated with sow reproductive performance. Embryo development and implantation in this period are accompanied by oxidative stress and inflammation. Gallnut tannic acid (GTA) has demonstrated strong antioxidant and anti-inflammatory properties; however, its effects on sow reproductive performance remain poorly defined. Here, we investigated the effects of dietary GTA supplementation during early gestation (days 7-30) on sow reproductive performance, gut microbiota, and underlying mechanisms. A total of 100 sows (Landrace × Large White) were allocated to four groups (n = 25 per group): a basal control diet (CON) or the basal diet supplemented with 0.05 % (I), 0.1 % (II), or 0.2 % (III) GTA. GTA supplementation tended to increase average litter size (P = 0.068), with the 0.1 % group (II) achieving the highest value (17.05 piglets per litter). GTA enhanced systemic antioxidant capacity by increasing serum total superoxide dismutase (T-SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) levels, whereas malondialdehyde (MDA). It also significantly reduced serum IL-6 concentrations levels (P < 0.05). In vitro, 6 μM tannic acid (TA) promoted trophoblast cell proliferation and upregulated the expression of implantation-related genes (PLET1, SPP1), antioxidant activity (CAT, CuZnSOD, MnSOD), an angiogenesis marker (VEGFR1), and the proliferation marker PCNA, while modulating inflammatory gene expression in porcine trophoblast (pTr2) cells (P < 0.05). Gut microbiota analysis revealed dose-dependent alterations, with the 0.2 % GTA group (III) showing the most pronounced compositional shifts at both phylum and family levels. In conclusion, dietary GTA supplementation during early gestation may improve sow reproductive performance by enhancing antioxidant capacity, regulating inflammatory homeostasis, and upregulating implantation-related gene expression. The optimal dietary level appears to be approximately 0.1 % GTA.