This experiment was conducted to investigate the effects of inulin supplementation in low- or high-fat diets on both the reproductive performance of sow and the antioxidant defence capacity in sows and offspring. Sixty Landrace × Yorkshire sows were randomly allocated to four treatments with low-fat diet (L), low-fat diet containing 1.5% inulin (LI), high-fat diet (H) and high-fat diet containing 1.5% inulin (HI). Inulin-rich diets lowered the within-litter birth weight coefficient of variation (CV, p = 0.05) of piglets, increased the proportion of piglets weighing 1.0-1.5 kg at farrowing (p < 0.01), reduced the loss of body weight (BW) and backfat thickness (BF) during lactation (p < 0.05) and decreased the duration of farrowing as well as improved sow constipation (p < 0.05). Sows fed fat-rich diets gained more BW during gestation (p < 0.01), farrowed a greater number of total (+1.65 pigs, p < 0.05) and alive (+1.52 pigs p < 0.05) piglets and had a heavier (+2.06 kg, p < 0.05) litter weight at birth as well as a decreased weaning-to-oestrous interval (WEI, p < 0.01) compared with sows fed low-fat diets. However, it is worth noting that the H diet significantly decreased the serum activities of superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) and increased the serum malondialdehyde (MDA) levels in sows and piglets (p < 0.05). In contrast, HI diet enhanced the activities of T-SOD and GSH-Px and decreased the serum MDA concentrations (p < 0.05) in sows and piglets. In summary, the fat-rich diets fed to sows during gestation had beneficial effects on reproductive performance, but aggravated the oxidative stress in sow and piglets. Inulin-rich diets fed to sow during gestation had beneficial effects on within-litter uniformity of piglet birthweight and enhanced the antioxidant defence capacity of sows and piglets.

The effect of dietary N-carbamylglutamate (NCG) supplementation during the entire gestation on reproductive performance of gilts was determined. At the initial day of gestation, forty-five cross-bred (Landrace × Large white) gilts were randomly assigned to five groups receiving a basal diet (control group) and basal diet supplemented with 0.05%, 0.10%, 0.15% and 0.20% NCG until parturition, respectively. At parturition, total litter size, live litter size and rate of stillbirth were not markedly affected by NCG supplementation. However, gilts in 0.05% NCG-supplemented group had more pigs born alive than gilts in control group (+1.11 pigs, p = 0.12), and live litter weight was increased (+12.13-19.17%, p < 0.05) in 0.05%, 0.10% and 0.15% NCG-supplemented groups relative to control group. And also, average birthweight of piglets born alive was higher (+6.57%, p < 0.05) in 0.05% NCG-supplemented group than in control group. Furthermore, on days 30, 60, 90 and 110 of gestation, concentrations of arginine and ornithine in plasma were higher (p < 0.05) in 0.05%, 0.10%, 0.15% and 0.20% NCG-supplemented groups than in control group, respectively. In addition, the chorioallantois gene expression of endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor A (VEGF-A), placental growth factor (PLGF) and angiopoietin-2 (ANG-2) was all increased (p < 0.05) in 0.05%, 0.10% and 0.15% NCG-supplemented groups than in control group. In conclusion, dietary supplementation with 500 mg/kg NCG during the entire gestation significantly improves pregnancy outcomes in gilts, which may be associated with the improved concentrations of arginine in plasma and placental angiogenic factors gene expression of gilts.