Effects of arginine supplementation during early gestation (day 1 to 30) on litter size and plasma metabolites in gilts and sows1

Two experiments were conducted, under typical commercial swine production conditions, to determine effects of dietary arginine supplementation during early gestation on the performance of gilts and sows. In Exp. 1, between d 1 and 30 of gestation, 62 Landrace gilts and 113 sows consumed a corn- and soybean meal–based diet supplemented with 1.3% L-arginine HCl or 2.2% L-alanine. Total numbers of piglets born (P< 0.05) and born alive (P< 0.01) per litter and litter birth weights of piglets born (P< 0.05) and born alive (P< 0.05) were increased in the arginine group compared with the control. In Exp. 2, 155 multiparous Landrace sows received 1.3% L-arginine HCl supplementation between d 1 and 14 (T2; n= 41), d 15 and 30 (T3; n= 40), or d 1 and 30 (T4; n= 37), whereas the control group received 2.2% L-alanine supplementation between d 1 and 30 (T1; n= 37). Blood samples were randomly obtained from 6 sows per group on d 1, 14, and 28 of gestation to determine plasma concentrations of AA and related metabolites. Total numbers of piglets born (P= 0.084) and born alive (P= 0.080) per litter tended to be higher for sows supplemented with arginine between d 1 and 14 of gestation (T2) than for control sows (T1). Concentrations of arginine and nitric oxide metabolites were greater (P< 0.05) in T4 compared with T1 and T3 on d 14 of gestation and were also greater in T4 compared with T1 and T2 on d 28 of gestation. Plasma concentrations of spermidine (P< 0.001) were increased in T3 and T4 compared with T1 and T2 on d 28. These results indicate that dietary arginine supplementation during early gestation improves the reproductive performance of gilts and sows, possibly via nitric oxide and polyamine-dependent mechanisms.