Diet xylo-oligosaccharide supplementation improves growth performance, immune function, and intestinal health of broilers

Abstract

The effects of xylo-oligosaccharides (XOS) on broiler growth performance, immune function, and intestinal health were investigated. A total of 540 one-d-old Arbor Acres Plus broilers were randomly divided into 5 groups with 6 replicates per group and 18 chickens per replicate. Broilers in the control (CON) group received a corn-soybean meal based basal diet, those in the antibiotics (ANT) group received the basal diet plus 500 mg/kg oxytetracycline, and those in XOS groups received the basal diet plus 150, 300, or 450 mg/kg XOS. Compared with CON, the body weight at 42 d and average daily gain from 1 to 42 d were significantly increased in the 150, 450 mg/kg XOS-added and ANT groups (P = 0.018), and the relative expression of claudin-1 and ZO-1 mRNA in the ileum was significantly higher in the 300 and 450 mg/kg XOS-added groups (P < 0.001). The feed conversion ratios (P < 0.001) and abdominal fat rates (P = 0.012) of broilers from 1 to 42 d of age were significantly lower in all XOS-added groups than in the control group. Splenic index (P = 0.036) and bursa of Fabricius index (P = 0.009) were significantly better in the ANT group and each XOS-added group than in the control group. Compared to CON and ANT, serum IgA (P = 0.007) and IgG (P = 0.002) levels were significantly higher in the 300 mg/kg XOS-added group, and the relative abundance of short-chain fatty acid-producing genera (Alistipes) was also significantly higher (P < 0.001). Meanwhile, ileal villus height (P < 0.001) and ratio of villus height to crypt depth (V:C) (P = 0.001) were significantly increased in XOS-added broilers. In analysis of relationships between cecal microbes and the physical barrier of the gut, [Ruminococcus]_torques_group was positively correlated with mRNA expression of ileal ZO-1 and claudin-1 (P < 0.05), and Bacteroides was positively correlated with increased ileal villus height and V:C (P < 0.05). Overall, XOS addition to broiler diets improved growth performance, promoted intestinal health by enhancing intestinal barrier function and regulating cecal microbiota diversity, and had positive effects on immunity.

Keywords: Broiler; Growth performance; Immunity; Intestinal health; Xylo-oligosaccharide.

Fig. 1

Relative expression of ileal tight junction protein mRNA. ZO-1 = zonula occludens-1. CON = basal diet; ANT = basal diet + 500 mg/kg calcium oxytetracycline; LXOS = basal diet + 150 mg/kg xylo-oligosaccharide; MXOS = basal diet + 300 mg/kg xylo-oligosaccharide; HXOS = basal diet + 450 mg/kg xylo-oligosaccharide. ^a–cColumns with different lowercase indicate a significant difference (P < 0.05).

Fig. 2

Phylum level species distribution map. CON = basal diet; ANT = basal diet + 500 mg/kg calcium oxytetracycline; LXOS = basal diet + 150 mg/kg xylo-oligosaccharide; MXOS = basal diet + 300 mg/kg xylo-oligosaccharide; HXOS = basal diet + 450 mg/kg xylo-oligosaccharide.

Fig. 3

Relative abundance of dominant bacteria at phylum level. CON = basal diet; ANT = basal diet + 500 mg/kg calcium oxytetracycline; LXOS = basal diet + 150 mg/kg xylo-oligosaccharide; MXOS = basal diet + 300 mg/kg xylo-oligosaccharide; HXOS = basal diet + 450 mg/kg xylo-oligosaccharide. ^a–eColumns with different lowercase indicate a significant difference (P < 0.05).

Fig. 4

Genus level species distribution map. CON = basal diet; ANT = basal diet + 500 mg/kg calcium oxytetracycline; LXOS = basal diet + 150 mg/kg xylo-oligosaccharide; MXOS = basal diet + 300 mg/kg xylo-oligosaccharide; HXOS = basal diet + 450 mg/kg xylo-oligosaccharide.

Fig. 5

Relative abundance of different bacteria at genus level. CON = basal diet; ANT = basal diet + 500 mg/kg calcium oxytetracycline; LXOS = basal diet + 150 mg/kg xylo-oligosaccharide. MXOS = basal diet + 300 mg/kg xylo-oligosaccharide. HXOS = basal diet + 450 mg/kg xylo-oligosaccharide. ^a–dColumns with different lowercase indicate a significant difference (P < 0.05).

Fig. 6

Heat map of correlation between indexes related to intestinal physical barrier function and cecal microbiota (genus level). UGG-014 and NK4A214 belong to the Ruminococcaceae, both of which are part of Firmicutes, the main fiber-degrading bacteria in the intestine. And [Ruminococcus]_torques_group is another subgroup in the Ruminococcaceae family, which can produce short-chain fatty acids. ZO-1 = zonula occludens-1; VH = villus height; CD = crypt depth; V:C = ratio of VH to CD. ∗ indicating P < 0.05; ∗∗ indicating P < 0.01.