Effects of dietary arginine supplementation on reproductive performance and immunity of sows

Arginine (Arg) is considered to have beneficial effects on placental development and function, as well as reproductive performance. The well-developed placenta is highly required in late gestation for rapid fetal growth, however, it is unknown if there is a crucial role of Arg in late gestation. Likewise, the immunological response of sows to Arg needs to be determined. Therefore, this study is designed to investigate the effects of dietary Arg supplementation on reproductive performance and immunity of sows. At day 30 of gestation, sixty sows (Landrace × Large White) were allocated to 3 groups receiving corn and soybean-based control diet (control group, n = 20), control diet supplemented with 1% l-arginine HCl until day 90 of gestation (Arg90 group, n = 20), and control diet supplemented with 1% l-arginine HCl until day 114 of gestation (Arg114 group, n = 20), respectively. Litter performance was recorded at parturition. Blood samples (n = 6) collected at days 30, 90, and 110 of gestation were measured for metabolic and immunological parameters. At parturition, total litter size was not affected by dietary Arg supplementation. As a result of less pigs born dead, however, sows in Arg114 group had more pigs born alive than sows in control group (+1.6 pigs, P < 0.05), total and live litter weights were increased (+1.6~2.1 kg, P < 0.05) in Arg114 group relative to both control and Arg90 groups. Compared with control group, dietary Arg supplementation increased (+12~110%, P < 0.05) plasma levels of ornithine, proline, and arginine at either day 90 (Arg90 and Arg110 groups) or day 110 of gestation (Arg110 group). Moreover, immune response was enhanced in Arg-supplemented sows, as indicated by the increased levels of serum immunoglobulin and porcine reproductive and respiratory syndrome virus (PRRSV) antibody. These findings indicate dietary Arg supplementation can improve litter performance and immune response, and the beneficial effect of Arg on fetal growth is evident in late gestation.