Contribution of L-Arginine supplementation during gestation on sow productive performance and on sow microbial faecal profile

Arginine plays an important role during reproduction, however, the amount of supplementation in sow diet is still uncertain. The aim of the study was to verify the efficacy of a gestating diet enriched or not with a low dose of L-arginine (Arg) on sow productive performance in terms of numbers and weight of piglets at birth and at weaning, frequency of intrauterine growth retardation (IUGR) and piglets’ mortality, sow placenta weight and salivary humoral immunity and intestinal microbial balance of the sows. 205 sows (Landrace x Large White) were divided into two experimental groups: a control group (CON) (102 sows) and a group supplemented with 0.25% of Arg (ARG) for the whole pregnancy period. Saliva and faecal samples were collected two days before farrowing and used for immunoglobulins and microbial analysis, respectively. Arg improved the number of total born piglets (p =.043) and tended to improve the number of total born alive (p =.086) and to reduce IUGR % (p =.090) and dead piglets at d0–d3 (p =.088). The weight of placenta and humoral immunity were not influenced by Arg. Arg did not modify the faecal microbial structure (alpha and beta indices) but increased the relative abundance of Bacteroidaceae family and Bacteroides genera (p =.0001). The results support the knowledge that Arg plays a key role in nutrition and physiology of pregnant sows without compromising gut eubiosis.Highlight Arg supplementation of sows’ gestation diet increased the number of total borns Arg supplementation of sows’ gestation diet did not negatively affect the sows’ gut eubiosis Arg plays a significant role in the nutrition of pregnant sows.