Effects Of Dietary Supplementation With L-arginine Or N-carbamylglutamate On Reproductive Performance And Immune Function Of Pregnant Sows Infected With PRRSV

The study was conducted to investigate effects of dietary supplementation with L-arginine (Arg) or N-carbamylglutamate (NCG) on reproductive performance and immune function of pregnant sows infected with porcine productive and respiratory syndrome virus (PRRSV). At d 30 of gestation, One hundred Yorkshire x Landrace multiparous sows infected with PRRSV were selected and randomly assigned to five treatment groups, three treatment groups were fed diet supplemented with 1.7% alanine (control diet, n=20),1% L-Arg (n=20) and 0.1% NCG (n=20) from d 30 to 90 of gestation, and all sows fed the control diet from d 91 of gestation to parturition, sows in other two treatment groups were fed diet supplemented with 1% L-Arg (n=20) and 0.1% NCG (n=20) until parturition. We recorded the number of stillbirths and their BW less than 900 g and their BW at birth, counted the total number of piglets and litter BW. Blood samples were collected at 2 h after feeding at d 30,90 and 110 of gestation. Plasma concentrations of amino acids were analyzed by automatic amino acid analyzer, plasma samples were assayed for urea and total protein concentrations by automatic biochemical analyzer, serum concentrations of NO were assayed using nitric acid reductase method, serum concentrations of TOS and immunoglobulin(IgG, IgM) concentration were assayed using a colorimetric method, serum levels of PRRSV-Ab, IL-10 and IFN-y were assayed using enzyme-linked immuneosorbent assay.The results were as follows:1. Dietary supplementation with L-arginine or N-carbamylglutamate from d 30 to 90 of gestation, compared with the control group:1.11% L-Arg supplementation increased the number of piglets born alive by 0.89 (P=0.061), and litter birth weight of piglets born alive by 1.02 kg (P=0.071); 0.1% NCG supplementation increased the number of pigs born alive by 0.33 (P>0.05); however, all of the measured indices did not differ between the 1% L-Arg and 0.1% NCG supplementation (P>0.05).1.21% L-Arg supplementation increased plasma concentrations of arginine, ornithine and proline (P<0.05), but serum levels of IFN-y at d 90 of gestation (P<0.05), serum levels of IgG increased at d 110 of gestation (P<0.05); 1% L-Arg and 0.1% NCG supplementation increased serum concentrations of NO and TOS(P<0.05), and serum levels of IgM, IgG and PRRSV-Ab(P<0.05), but reduced plasma concentrations of urea at d 90 of gestation (P<0.05); Plasma concentrations of arginine and ornithine(P<0.05), and serum levels of IgG were higher in the 1% L-Arg supplementation than in the 0.1% NCG supplementation (P<0.05).2. Dietary supplementation with L-arginine or N-carbamylglutamate from d 30 of gestation to parturition, compared with the control group:2.11% L-Arg and 0.1% NCG supplementation increased the number of piglets born alive by 1.33 (P<0.05) and 0.5 (P>0.05), and litter birth weight of piglets born alive by 2.70 and 1.21 kg (P<0.05), respectively,1% L-Arg supplementation increased BW of piglets born alive by 4.86%(P<0.05) and reduced the rate of stillbirths by 75.88%; compared with 0.1% NCG supplementation,1% L-Arg supplementation increased the number of piglets born alive by 0.83 (P=0.075), and litter birth weight of piglets born alive by 1.49 kg (P<0.05), but reduced the rate of stillbirths by 67.15%(P<0.05).2.21% L-Arg supplementation increased plasma concentrations of arginine, ornithine, proline (P<0.05), and serum levels of IgM, IgG and PRRSV-Ab(P<0.05), but reduced levels of IFN-γ(P<0.05),1% L-Arg and 0.1% NCG supplementation increased serum concentrations of NO and TOS (P<0.05), but reduced plasma concentrations of urea at d 90 and 110 of gestation (P<0.05); 1% L-Arg supplementation increase levels of IL-10 at d 110 of gestation (P<0.05),0.1% NCG supplementation increased serum levels of IgM, IgG and PRRSV-Ab at d 90 of gestation (P<0.05), levels of IgM, IgG and IL-10 increased significantly at d 110 of gestation (P<0.05); plasma concentration of arginine and ornithine (P<0.05), and serum levels of IgG were significantly higher in 1% L-Arg supplementation compared with 0.1% NCG supplementation at d 90 of gestation (P<0.05). 3. Dietary supplementation with L-arginine or N-carbamylglutamate from d 30 of gestation to parturition compared with from d 30 to 90 of gestation:3.11% L-Arg supplementation increased litter birth weight of piglets born alive by 1.68 kg (P<0.05), and BW of piglets born alive by 7.09% (P<0.05), but reduced the rate of stillbirths by 67.05%(P<0.05); 0.1% NCG supplementation increased BW of piglets born alive by 4.23%(P=0.096).3.2 At d 110 of gestation,1% L-Arg supplementation increased plasma concentrations of arginine, ornithine and proline (P<0.05), and serum concentrations of NO and TOS, and serum levels of IgG and IL-10(P<0.05), but reduced serum levels of IFN-y (P<0.05); 0.1% NCG supplementation increased serum levels of IgM and IgG (P<0.05); 1% L-Arg and 0.1% NCG supplementation reduced plasma concentrations of urea (P>0.05).Conclusion:1. Dietary supplementation with L-Arg or NCG improved the reproductive performance of pregnant sows by improving the utilization of amino acids and immune function, and reducing the rate of piglets body weight less than 900 g and stillbirths.2. Effects of dietary supplementation with L-arginine or N-carbamylglutamate on reproductive performance were better during middle and late gestation than during middle gestation, and L-Arg were better than NCG supplementation.