Bioregional Alterations in Gut Microbiome Contribute to the Plasma Metabolomic Changes in Pigs Fed with Inulin

Abstract

Inulin (INU) is a non-digestible carbohydrate, known for its beneficial properties in metabolic disorders. However, whether and how gut microbiota in its regulation contributes to host metabolism has yet to be investigated. We conduct this study to examine the possible associations between the gut microbiota and circulating gut microbiota–host co-metabolites induced by inulin interventions. Plasma and intestinal site samples were collected from the pigs that have consumed inulin diet for 60 days. High-throughput sequencing was adopted for microbial composition, and the GC-TOF-MS-based metabolomics were used to characterize featured plasma metabolites upon inulin intervention. Integrated multi-omics analyses were carried out to establish microbiota–host interaction. Inulin consumption decreased the total cholesterol (p = 0.04) and glucose (p = 0.03) level in serum. Greater β-diversity was observed in the cecum and colon of inulin-fed versus that of control-fed pigs (p < 0.05). No differences were observed in the ileum. In the cecum, 18 genera were altered by inulin, followed by 17 in the colon and 6 in the ileum. Inulin increased propionate, and isobutyrate concentrations but decreased the ratio of acetate to propionate in the cecum, and increased total short fatty acids, valerate, and isobutyrate concentrations in the colon. Metabolomic analysis reveals that indole-3-propionic acid (IPA) was significantly higher, and the branched-chain amino acids (BCAA), L-valine, L-isoleucine, and L-leucine are significantly lower in the inulin groups. Mantel test and integrative analysis revealed associations between plasma metabolites (e.g., IPA, BCAA, L-tryptophan) and inulin-responsive cecal microbial genera. These results indicate that the inulin has regional effects on the intestine microbiome in pigs, with the most pronounced effects occurring in the cecum. Moreover, cecum microbiota plays a pivotal role in the modulation of circulating host metabolites upon inulin intervention

Highly Branched Neo-Fructans (Agavins) Attenuate Metabolic Endotoxemia and Low-Grade Inflammation in Association with Gut Microbiota Modulation on High-Fat Diet-Fed Mice

“…A previous work showed that l-leucine and l-valine are involved in regulation of food intake through gut satiety hormones [52], while other investigations have evidenced that these essential amino acids are associated with body weight regulation, insulin, and glucose homeostasis [53,54]. In a very recent study, Wu and colleagues identified l-leucine, l-isoleucine and l-valine as biomarkers in plasma of pigs that received an inulin supplement [55]. These branched amino acids were lower after inulin intervention and positively associated to total cholesterol and glucose levels [55]; nonetheless, these results are disagreed with the present study, because we detected a high content of l-leucine and l-valine which inversely correlated with cholesterol and glucose levels.…”

Modulation of Pectin on Mucosal Innate Immune Function in Pigs Mediated by Gut Microbiota

“…Total bacterial DNA was extracted from the mucosa of pigs, using the Qiagen DNA isolation kit (Qiagen, Hilden, Germany), according to the manufacturer's instructions. For 16S ribosomal RNA (rRNA) gene-based microbial composition profiling, barcoded amplicons from the V3-V5 region of 16S rRNA genes were generated by a 2-step PCR protocol, and the 16S rRNA gene was sequenced on the Illumina HiSeq sequencing platform, as described before [25]. Raw Illumina fastq files were demultiplexed, quality filtered and analyzed, using QIIME 1.8.0 [26], as described previously [25], while using the Silva 123 reference database.…”

“…For 16S ribosomal RNA (rRNA) gene-based microbial composition profiling, barcoded amplicons from the V3-V5 region of 16S rRNA genes were generated by a 2-step PCR protocol, and the 16S rRNA gene was sequenced on the Illumina HiSeq sequencing platform, as described before [25]. Raw Illumina fastq files were demultiplexed, quality filtered and analyzed, using QIIME 1.8.0 [26], as described previously [25], while using the Silva 123 reference database. Predictive functional profiling of microbial communities was conducted by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PIRCUSt) [27].…”

Sanitary Conditions Affect the Colonic Microbiome and the Colonic and Systemic Metabolome of Female Pigs

“…The nutrient composition of intestinal digesta is dependent of diet composition and processes of nutrient hydrolysis, fermentation, and absorption in the gut (14,15). Related complex changes in composition can be studied by measuring changes and differences in the gut metabolome (16,17). Metabolomics offer the possibility to study many metabolites simultaneously in a single sample (18).…”