Tryptophan Supplementation Enhances Intestinal Health by Improving Gut Barrier Function, Alleviating Inflammation, and Modulating Intestinal Microbiome in Lipopolysaccharide-Challenged Piglets
Tryptophan (Trp) can modify the gut microbiota. However, there is no information about the effect of Trp on intestinal microbiota after lipopolysaccharide (LPS) challenge. This study aimed to investigate the effect of Trp on intestinal barrier function, inflammation, antioxidant status, and microbio...
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Published in | Frontiers in microbiology Vol. 13; p. 919431 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Frontiers Media S.A
04.07.2022
|
Subjects | |
Online Access | Get full text |
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Summary: | Tryptophan (Trp) can modify the gut microbiota. However, there is no information about the effect of Trp on intestinal microbiota after lipopolysaccharide (LPS) challenge. This study aimed to investigate the effect of Trp on intestinal barrier function, inflammation, antioxidant status, and microbiota in LPS-challenged piglets. A total of 18 weaned castrated piglets were randomly divided into three treatments with 6 replicate per treatment, namely, (i) non-challenged control (CON); (ii) LPS-challenged control (LPS-CON); and (iii) LPS + 0.2% Trp (LPS-Trp). After feeding with control or 0.2% tryptophan-supplemented diets for 35 days, pigs were intraperitoneally injected with LPS (100 μg/kg body weight) or saline. At 4 h post-challenge, all pigs were slaughtered, and colonic samples were collected. The samples were analyzed for gut microbiota, fatty acids, antioxidant parameters, and the expression of mRNA and protein. The community bar chart showed that Trp supplementation to LPS-challenged pigs increased the relative abundance of
Anaerostipes
(
P
< 0.05) and tended to increase the relative abundance of
V9D2013_group
(
P
= 0.09), while decreased the relative abundance of
Corynebacterium
(
P
< 0.05) and
unclassified_c__Bacteroidia
(
P
< 0.01). Gas chromatography showed that Trp increased the concentrations of acetate, propionate, butyrate, and isovalerate in the colonic digesta (
P
< 0.05). Trp reduced the mRNA level of pro-inflammatory cytokines (
P
< 0.01), and increased mRNA level of aryl hydrocarbon receptor, cytochrome P450 (
CYP
)
1A1
and
CYP1B1
(
P
< 0.05). Correlation analysis results showed that acetate, propionate, and butyrate concentrations were positively correlated with mRNA level of
occludin
and
CYP1B1
(
P
< 0.05), and were negatively correlated with pro-inflammatory cytokines gene expression (
P
< 0.05). Isovalerate concentration was positively correlated with catalase activity (
P
< 0.05), and was negatively correlated with pro-inflammatory cytokines gene expression (
P
< 0.05). Furthermore, Trp enhanced the antioxidant activities (
P
< 0.01), and increased mRNA and protein expressions of claudin-1, occludin, and zonula occludens-1 (
P
< 0.01) after LPS challenge. These results suggest that Trp enhanced intestinal health by a modulated intestinal microbiota composition, improved the short chain fatty acids synthesis, reduced inflammation, increased antioxidant capacity, and improved intestinal barrier function. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 This article was submitted to Microorganisms in Vertebrate Digestive Systems, a section of the journal Frontiers in Microbiology Reviewed by: Ruqing Zhong, Institute of Animal Sciences (CAAS), China; Hongbo Yi, Guangdong Academy of Agricultural Sciences (GDAAS), China; Matteo Dell’Anno, University of Milan, Italy Edited by: Xiangfeng Kong, Institute of Subtropical Agriculture (CAS), China |
ISSN: | 1664-302X 1664-302X |
DOI: | 10.3389/fmicb.2022.919431 |