Dietary butyrate glycerides modulate intestinal microbiota composition and serum metabolites in broilers

Abstract

Butyrate can modulate the immune response and energy expenditure of animals and enhance intestinal health. The present study investigated changes in the intestinal microbiota composition and serum metabolites of young broilers in response to 3,000 ppm butyrate in the form of butyrate glycerides (BG) via pyrosequencing of bacterial 16S rRNA genes and nuclear magnetic resonance (NMR). The dietary treatment did not affect the alpha diversity of intestinal microbiota, but altered its composition. Thirty-nine key operational taxonomic units (OTUs) in differentiating cecal microbiota community structures between BG treated and untreated chickens were also identified. Bifidobacterium was, in particular, affected by the dietary treatment significantly, showing an increase in not only the abundance (approximately 3 fold, P ≤ 0.05) but also the species diversity. The (NMR)-based analysis revealed an increase in serum concentrations of alanine, low-density and very low-density lipoproteins, and lipids (P ≤ 0.05) by BG. More interestingly, the dietary treatment also boosted (P ≤ 0.05) serum concentrations of bacterial metabolites, including choline, glycerophosphorylcholine, dimethylamine, trimethylamine, trimethylamine-N-oxide, lactate, and succinate. In conclusion, the data suggest the modulation of intestinal microbiota and serum metabolites by BG dietary treatment and potential contribution of intestinal bacteria to lipid metabolism/energy homeostasis in broilers.

Figure 1

Effects of butyrate glycerides on the β-diversity of ileal microbiota. Two dimensional plots of PCoA are based on the unweighted UniFrac distance (B). ANOSIM is based on the unweighted UniFrac distance between microbial communities (C). BD: basal diet; BG: BD supplemented with butyrate glycerides.

Figure 2

Effects of butyrate glycerides on the β-diversity of cecal microbiota. Two dimensional plots of PCoA are based on the unweighted UniFrac distance (B). ANOSIM is based on the unweighted UniFrac distance between microbial communities (C). BD: basal diet; BG: BD supplemented with butyrate glycerides.

Figure 3

Heat map of the key OTUs identified in the cecal microbiota. The OTUs are identified by SPLS-DA as key variables for the differentiation of microbial profiles in the cecal microbiota of BG-treated and untreated (BD) groups. Percentage composition based on the 16S rRNA sequence is indicated by the color intensity. N = 6; 1, 2, 3, 4, 5, 6: number of the birds. The color key value indicates relative abundance of an OUT expressed as percentage of total number of sequences for an individual bird.

Figure 4

Pattern recognition with SIMCA-P 13.0. The PCA score plot (A), PLS-DA score plot (B), PLS-DA validation plots (permutation number: 200) (C), as well as OPLS-DA score plot (D) were derived from ¹H NMR serum spectra of the BG-fed group compared with BD-fed chickens. Corresponding S-plot between BG-fed and BD-fed chickens, indicating the metabolites that changed significantly (panel E): 1, LDL/VLDL; 2, lipids; 3, lactate; 4, alanine; 5, succinate; 6, dimethylamine; 7, trimethylamine; 8, choline; 9, GPC; 10, TMAO.