Abstract
A total of 40 crossbred healthy male weaned piglets (weaned at 28 d of age) was used to investigate whether dietary Tryptophan (Trp) supplementation attenuate the intestine injury in lipopolysaccharides (LPS) challenged weaning pigs. Animals were randomly assigned into 5 groups: (1) control group (CON); (2) LPS group (LPS); (3) 0.2% Trp group (TRP); (4) LPS + 0.2% Trp group; (5) LPS + 0.4% Trp group. On days 10, 20, and 28 of the trial, piglets in LPS, LPS+0.2% Trp, and LPS+0.4% Trp groups were challenged with LPS (80 μg/kg body weight), whereas those in the CON and 0.2% Trp groups received the same volume of sterile saline. All piglets were sacrificed at 29 days. Our results showed that the final body weight, average daily gain and average daily feed intake in LPS group were decreased compared with those in CON group (P<0.05). Compared with LPS group, the diarrhea rate in the CON, LPS+0.2%Trp and LPS+0.4%Trp group was significantly decreased (P<0.05). Compared with LPS group, dietary Trp supplementation increased activities of CAT, T-AOC, and T-SOD in serum, as well as CAT in liver of LPS+0.2% Trp, and LPS+0.4% Trp groups (P<0.05). The villus height, crypt depth, and muscle layer thickness in intestine were significantly higher in LPS+0.2%Trp and LPS+0.4%Trp groups than those in LPS group (P<0.05). TEM showed that intestinal tight junctions in TRP, LPS+0.2%Trp and LPS+0.4%Trp groups remained intact and integrity than that of LPS group. Additionally, dietary 0.2% Trp supplementation increased the mRNA expression of ZO-1 and occludin-1, while LPS decreased ZO-1 and Occludin-1 levels (P<0.05). In conclusion, dietary Trp supplementation could alleviate the intestinal injury through increasing antioxidant ability and maintaining intestinal barrier in lipopolysaccharides (LPS) challenged weaning pigs.
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