0
A total of 24 Large White x Landrace piglets of 5.0 kg were randomly allotted to 1 of the 3 experimental diets. Animals were individually housed in pens. A basal diet was formulated to contain low levels of arginine, two additional diets were formulated by supplementation of the basal diet with 0.7 and 1.2% L-arginine-free base. Faecal samples of each animal were daily collected in order to determinate moisture and to calculate the incidence of diarrhoea. Body weight and feed intake was measured on days 0 and 10. Blood samples were collected on days 3, 6 and 10 for measuring plasma amino acids. On day 10, six piglets from each group were randomly selected to be euthanized in order to collect duodenum, jejunum and ileal samples for histological analysis.
The dietary supplementation with 0.7% of L-arginine increased immunoreactive expression of CD34 in duodenal sub-mucosa, ileal mucosa and sub-mucosa, and expression of vascular endothelial growth factor in duodenal sub-mucosa, jejunal mucosa and sub-mucosa, and ileal mucosa compared with the control and 1.2% L-arginine inclusion. Dietary supplementation with 1.2% of L-arginine increased the concentration of jejunal endothelin-1 compared with the animals fed the control diet. Immunoexpresion of VEGF in duodenal mucosa and plasma lysine concentrations on days 6 and 10 were lower in pigs supplemented with 1.2% of L-arginine than those fed the control diet.
It is concluded that the effect of L-arginine on microvascular development are beneficial at lower levels but have adverse effects at higher intakes. Therefore, a 0.7% of L-arginine supplementation may be a useful method to improve microvascular development in the small intestine of early-weaned piglets.
Z Zhan, D Ou, X Piao, SW Kim, Y Liu and J Wang, 2008. The journal of Nutrition 138:1304-1309.
