Background: Placental angiogenesis is crucial for ensuring placental function and normal fetal development. It has been demonstrated that elevated plasma levels of homoarginine (hArg), an endogenous amino acid, during pregnancy correlate with enhanced vascular endothelial function. However, the effect of hArg in placental angiogenesis during pregnancy is still ambiguous. This study seeks to evaluate the impact of supplemental hArg during the rapid placental growth phase in early pregnancy, a key moment for placental angiogenesis, on ultimate pregnancy outcomes and placental angiogenesis in rats, as well as its potential processes. Methods: This study utilized thirty 8-week-old female Sprague Dawley rats as pregnant animals, which were randomly allocated to control and treatment groups (15 per group) and administered 20 mg/kg of hArg from embryonic day 0.5 (E0.5) to E13. The dams were euthanized on E21. Results: Maternal hArg dietary supplementation positively influenced pregnancy outcomes, resulting in a significant increase in the number of live-born offspring and total placental weight, alongside elevated maternal circulating reproductive hormone levels. Additionally, the upregulation of the amino acid transporter in the placenta of the treatment group established a basis for hArg accumulation in the placenta, hence promoting hArg-specific augmentation of eNOS-mediated NO production. The treated group simultaneously demonstrated an expanded labyrinthine zone, increased blood sinusoids area, enhanced vascular density, and raised levels of proangiogenic factors. Mechanistically, hArg enhanced the expression of proteins linked with the PI3K/AKT signaling pathway. Conclusions: Supplementation with hArg during the placenta’s rapid growth phase enhances placental angiogenesis, ultimately enhancing pregnancy outcomes. This effect may be attributed to the regulation of the PI3K/AKT signaling pathway.

To investigate the regulatory effects of dietary fiber structure (β-glucan-to-arabinoxylan ratio, β/AX) and apparent viscosity (AV) on production performance in pigs, this study used a 2 × 3 factorial design, randomly assigning 36 growing pigs (47.2 ± 1.5 kg) to six dietary treatments (two AV levels and three β/AX ratios), and observed the growth performance, carcass traits, meat quality, intestinal microbiota, and liver lipid metabolism. The results showed that increased dietary β/AX and AV reduced subcutaneous fat deposition, improved meat tenderness and the nutrient content of meat, but decreased pig weight gain and dressing percentage. Increased dietary β/AX and AV selectively promoted the relative abundance of butyrate-producing bacteria and the concentration of butyrate in the middle colon, thereby regulating the expression of genes related to hepatic de novo lipid synthesis and oxidation, reducing serum glucose and total cholesterol levels, and increasing plasma glucagon-like peptide-1. These findings reveal the potential mechanism by which the physicochemical properties of dietary fiber mediate lipid metabolism to reduce weight gain and provide new insights for regulating fat deposition in pigs by controlling the structural and physical properties of dietary fiber.