Enterococcus faecium Modulates the Gut Microbiota of Broilers and Enhances Phosphorus Absorption and Utilization

SIMPLE SUMMARY: Bone health is an important factor in broiler production. Among the key nutrients affecting bone health, phosphorus (P) plays a great role. Enterococcus faecium has been widely used as feed additive to promote growth performance of broilers. There were reports suggesting that E. faecium improved skeletal health of rats. However, the effect of E. faecium on the bones of broilers remains unclear. The present study is to investigate the effect of E. faecium on P absorption and utilization in broilers and the associated changes in the gut microbiota. Dietary inclusion with E. faecium did not improve broiler performance in this study but improved P absorption and bone mineralization. In E. faecium-treated broilers, the expression of intestinal type IIb sodium-dependent phosphate cotransporter (NaP-IIb) mRNA was upregulated and the concentration of serum alkaline phosphatase was increased. Dietary supplementation with E. faecium changed the gut microbiota populations of broilers and increased the relative abundance of SCFA (short-chain fatty acid)-producing bacteria. The changed populations of microbiota improved intestinal P absorption and bone forming metabolic activities. In conclusion, dietary inclusion with E. faecium facilitates increased utilisation of P in broilers. ABSTRACT: Modern broiler chickens have ongoing bone health problems. Phosphorus (P) plays an important role in bone development and increased understanding of P metabolism should improve the skeletal health of broilers. Enterococcus faecium has been widely used as a probiotic in broiler production and is shown to improve skeletal health of rats, but its effect on the bones of broilers remains unclear. This study investigated the effect of E. faecium on P absorption and utilization in broilers and the associated changes in the gut microbiota using 16S rDNA sequencing. Dietary supplementation with E. faecium improved P absorption through upregulation of the expression of intestinal NaP-IIb mRNA and increased the concentration of serum alkaline phosphatase. These actions increased P retention and bone mineralization in E. faecium-treated broilers. The positive effects of E. faecium on P metabolism were associated with changes in the populations of the intestinal microbiota. There was increased relative abundance of the following genera, Alistipes, Eubacterium, Rikenella and Ruminococcaceae and a decrease in the relative abundance of Faecalibacterium and Escherichia-Shigella. Dietary supplementation with E. faecium changed gut microbiota populations of broilers, increased the relative abundance of SCFA (short-chain fatty acid)-producing bacteria, improved intestinal P absorption and bone forming metabolic activities, and decreased P excretion. E. faecium facilitates increased utilisation of P in broilers.