Dietary Supplementation With Citrus Extract Altered the Intestinal Microbiota and Microbial Metabolite Profiles and Enhanced the Mucosal Immune Homeostasis in Yellow-Feathered Broilers.

Miao Yu,Weidong Chen,Gang Wang,Xianyong Ma,Zhenming Li,Yiyan Cui

doi:10.3389/fmicb.2019.02662

Abstract

The present study aimed to investigate the effects of citrus extract (CE) on intestinal microbiota, microbial metabolite profiles, and the mucosal immune status in broilers. A total of 540 one-day-old yellow-feathered broilers were randomly allotted into three groups and fed a basal diet (control group), or a basal diet containing 10 mg/kg of zinc bacitracin (antibiotic group), or 10 mg/kg of CE (CE group). Each treatment consisted of six replicates, with 30 broilers per replicate. After 63-day feeding, two broilers per replicate were randomly selected and slaughtered, and their ileal and cecal digesta and ileal tissue were collected for microbial composition, microbial metabolites, and gene expression analysis. The results showed that CE significantly increased the abundance of Barnesiella and Blautia than did the antibiotic group (adjusted P < 0.05), whereas it decreased the abundance of Alistipes and Bacteroides (adjusted P < 0.05). Meanwhile, the CE group also increased the numbers of Bifidobacterium and Lactobacillus than did the control and antibiotic groups (P < 0.05), whereas it decreased the number of Escherichia coli (P < 0.05). For microbial metabolites, dietary supplementation with CE increased the concentrations of lactate, total short-chain fatty acids, acetate, and butyrate in the cecum than did the control and antibiotic groups (P < 0.05), whereas it decreased the concentrations of amino acid fermentation products (ammonia, amines, p-cresol, and indole) (P < 0.05). Additionally, supplementation with CE up-regulated (P < 0.05) the mRNA expression of intestinal barrier genes (ZO-1 and Claudin) in the ileum than did both the control and antibiotic groups. However, antibiotic treatment induced gut microbiota dysbiosis, altered the microbial metabolism, and disturbed the innate immune homeostasis. In summary, these results provide evidence that dietary supplementation with CE can improve the intestinal barrier function by changing microbial composition and metabolites, likely toward a host-friendly gut environment. This suggests that CE may possibly act as an efficient antibiotic alternative for yellow-feathered broiler production.

Highlights

In-feed antibiotics have been extensively used as growth promoters in livestock production to maintain health and to improve feed conversion efficiency, utilization, and growth performance (Castanon, 2007)
To test the hypothesis that citrus extract (CE) as an antibiotic alternative may positively alter the microbial community and its metabolites, and that these alterations can modulate the mucosa immune response in yellow-feathered broilers, the current study investigated the effects of dietary supplementation with CE on the microbial community, microbial metabolite profiles, and expression of immune-related genes in the intestine
The results showed that dietary supplementation with CE dramatically increased the number of Bifidobacterium and up-regulated the mRNA expression of intestinal barrier genes (ZO-1 and Claudin) in the ileum, whereas it decreased the number of E. coli

Summary

Introduction

In-feed antibiotics have been extensively used as growth promoters in livestock production to maintain health and to improve feed conversion efficiency, utilization, and growth performance (Castanon, 2007). Several previous studies reported that the dietary supplementation with citrus products in broiler feed could enhance growth performance (Seidavi et al, 2015), stimulate IgG and IgM antibody production in serum (Pourhossein et al, 2015), and decrease the number of E. coli in the cecum digesta by using a culture-based approach (Ebrahimi et al, 2015; Alefzadeh et al, 2016). These results indicated that CE can modulate the intestinal microbiota and immune system activities. Whether dietary supplementation with CE affects the intestinal microbial metabolites in broilers remains unclear

Methods

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Discussion

Conclusion