N-carbamylglutamate and L-arginine improved maternal and placental development in underfed ewes

Abstract

The objectives of this study were to determine how dietary supplementation of N-carbamylglutamate (NCG) and rumen-protected L-arginine (RP-Arg) in nutrient-restricted pregnant Hu sheep would affect (1) maternal endocrine status; (2) maternal, fetal, and placental antioxidation capability; and (3) placental development. From day 35 to day 110 of gestation, 32 Hu ewes carrying twin fetuses were allocated randomly into four groups: 100% of NRC-recommended nutrient requirements, 50% of NRC recommendations, 50% of NRC recommendations supplemented with 20 g/day RP-Arg, and 50% of NRC recommendations supplemented with 5 g/day NCG product. The results showed that in maternal and fetal plasma and placentomes, the activities of total antioxidant capacity and superoxide dismutase were increased (P < 0.05); however, the activity of glutathione peroxidase and the concentration of maleic dialdehyde were decreased (P < 0.05) in both NCG- and RP-Arg-treated underfed ewes. The mRNA expression of vascular endothelial growth factor and Fms-like tyrosine kinase 1 was increased (P < 0.05) in 50% NRC ewes than in 100% NRC ewes, and had no effect (P > 0.05) in both NCG- and RP-Arg-treated underfed ewes. A supplement of RP-Arg and NCG reduced (P < 0.05) the concentrations of progesterone, cortisol, and estradiol-17β; had no effect on T4 /T3 ; and improved (P < 0.05) the concentrations of leptin, insulin-like growth factor 1, tri-iodothyronine (T3 ), and thyroxine (T4 ) in serum from underfed ewes. These results indicate that dietary supplementation of NCG and RP-Arg in underfed ewes could influence maternal endocrine status, improve the maternal-fetal-placental antioxidation capability, and promote fetal and placental development during early-to-late gestation.