Dietary L-arginine supplementation enhances intestinal development and expression of vascular endothelial growth factor in weanling piglets.

Oral administration of L-arginine has been reported to prevent gut disease in human infants. However, little is known about the effects of dietary arginine supplementation on intestinal development of weaned piglets. In the present study, twenty 21-d-old castrated piglets with 5·3 (SEM 0·13) kg body weight (BW) were weaned from sows, individually housed and randomly assigned to one of the two maize- and soyabean meal-based diets supplemented with 0 or 1% L-arginine. After consuming the diets for 7 d, six pigs were randomly selected from each group to obtain various tissues. Compared with control pigs, dietary supplementation with 1% L-arginine did not affect feed intake but enhanced (P<0·05) the relative weight of the small intestine (+33 %), daily BW gain (+38 %) and feed efficiency (+28 %). The villus height of the duodenum, jejunum and ileum in arginine-supplemented piglets was 21, 28 and 25% greater (P<0·05) than in the nonsupplemented control group. Arginine supplementation increased (P<0·05) protein levels for vascular endothelial growth factor(VEGF) in duodenal, jejunal and ileal mucosae by 14, 39 and 35 %, respectively. Compared with the control group, dietary supplementation with 1% L-arginine increased (P<0·05) plasma concentrations of arginine and insulin (+36 %), and decreased (P<0·05) plasma concentrations of cortisol (233 %), NH3 (221 %) and urea (219 %). These results indicate that arginine supplementation enhances intestinal growth, development and expression of VEGF in early-weaned pigs fed a maize- and soyabean meal-based diet. The findings may have important implications for neonatal pigs under stressful or diseased conditions.