Resveratrol and β-hydroxy-β-methylbutyric acid supplementation promotes ileal development and digestive function by altering microbial community abundance and metabolites in Tibetan sheep

Abstract

Introduction: The effects of resveratrol (RES) and β-hydroxy-β-methylbutyric acid (HMB) on phenotype, immunity, digestive enzyme activity and short-chain fatty acids (SCFAs) contents in ileum of Tibetan sheep were investigated.

Methods: A total of 120 two-month-old Tibetan sheep (15.5 ± 0.14 kg) were randomly allocated to 4 treatments: control group (basal diet), RES group (basal diet +1.5 g RES/d), HMB group (basal diet +1.25 g HMB/d), RES-HMB group (basal diet +1.5 g RES/d + 1.25 g HMB/d).

Results: Results indicated that dietary RES and (or) HMB supplementation significantly improved the phenotype (mucosal thickness and villus width), SCFAs concentrations, and digestive enzymes (lipase, cellulase, and α-amylase) (p < 0.05). The relative abundance of Brevibacillus, Clostridium sensu stricto 3, and Eubacterium hallii group were increased, while the abundance of Ruminococcus and Mogibacterium were decreased (p < 0.05) in the RES-HMB group. The metabolic profiling indicated an increase in the differential metabolites (DMs) including L-arginine, butanoic acid, D-mannose, and retinol were increased in the RES-HMB group (p < 0.05).

Discussion: In summary, our results suggested that RES and (or) HMB supplementation improved SCFAs concentration by up-regulating the microbial community abundance (Brevibacillus, Clostridium sensu stricto 3, and Eubacterium hallii group) and metabolism (L-arginine, butanoic acid, D-mannose, and retinol), thus contributing to ileal morphology and digestive enzyme activity. These findings may provides a novel reference for the nutritional regulation to improve the production of Tibetan sheep.

Keywords: Tibetan sheep; ileum; metabolite; microorganism; resveratrol; β-hydroxy-β-methylbutyric acid.

Figure 1

(A–D) Section of ileal tissue. (A) C group. (B) RES addition group. (C) HMB addition group. (D) RES-HMB addition group. H&E staining, 100× magnification. (E–J) Effects of RES or HMB on the morphology and development of ileal in Tibetan sheep. In the same figure, no letter or the same letter superscript indicates no significant difference (p > 0.05), while different lowercase letters superscript indicates significant differences (p < 0.05). The same below.

Figure 2

Richness and diversity of the ileal microflora. (A) OTUs Venn diagram for experimental groups and C group. (B) The Goods_coverage of the four groups. (C–E) Alpha diversity as presented by Shannon, Chao1, ACE in the ileum of Tibetan sheep among groups. (F) Principal coordinate analysis based on Bray-Curtis distance.

Figure 3

Composition of the ileal microbiota of Tibetan sheep at phylum (A) and genus (B) level. (C–G) Histogram showing differences in the contents of microflora taxonomic groups at the genus level.

Figure 4

Differential metabolites and metabolic pathways between the experimental and control groups. (A) Volcano plot showing differential metabolites in the ileal tissues from the C-RES group. (B) Volcano plot showing differential metabolites in the ileal tissues from the C-HMB group. (C) Volcano plot showing differential metabolites in the ileal tissues from the C-RES-HMB group. (D–F) KEGG pathway enrichment analysis of ileal metabolites. RES group (D), HMB group (E), and RES-HMB group (F) compared with the C group. Differentially expressed metabolites were subjected to pathways enrichment analysis.