Tryptophan increases intestinal permeability and decreases intestinal tight junction protein expression in weanling piglets

摘要

Tryptophan enhances antioxidant activity and intestinal development. The purpose of this study was to investigate whether Trp could improve intestinal barrier integrity in weaned piglets. Twenty-one weaned piglets were randomly assigned to 3 groups: a control group (a basal feed containing 0.1% Trp) and 2 Trp-supplemented groups (a basal feed plus 0.1 or 0.2% Trp). Tryptophan, 0.2%, increased serum diamine oxidase activity (P 0.05) and 0.1% Trp increased the serum endotoxin concentration (P 0.05), suggesting that Trp increased intestinal permeability. Compared with the control group, 0.2% Trp significantly decreased the abundance of occludin, zonula occludens-1 (ZO-1), and claudin-1 in the ileum of weanling piglets, whereas 0.1% Trp decreased only the abundance of occludin. Furthermore, compared with the control group, 0.2% Trp significantly decreased the mRNA expression of occludin, ZO-1, and claudin-1 in the ileum of weanling piglets. In conclusion, Trp above the recommended intake increased intestinal permeability and decreased the intestinal expression of tight junction proteins in weanling piglets.