Effects of dietary supplement with licorice and rutin mixture on production performance, egg quality, antioxidant capacity, and gut microbiota in quails (Turnix tanki)

Abstract

This study was conducted to evaluate the effect of licorice and rutin on production performance, egg quality, and mucosa antioxidant levels in Chinese yellow quail. A total of 240 Chinese Yellow Quail (400-day-old) were randomly distributed into 5 groups: the Control group, fed with a basic diet; the LR1 group, fed with basal diet supplemented with 300 + 100 mg licorice and rutin mixture/kg diet; the LR2 group, fed with basal diet supplemented with 300 + 200 mg licorice and rutin mixture/kg diet; the LR3 group, fed with basal diet supplemented with 600 + 100 mg licorice and rutin mixture/kg diet and the LR4 group, fed with basal diet supplemented with 600 + 200 mg licorice and rutin mixture/kg diet. Compared with the control, supplementation with the licorice and rutin mixture improved the laying rate and eggshell thickness whereas decreased the feed conversion ratio of quails. Moreover, dietary supplementation with the licorice and rutin mixture improved the antioxidant capacity by increasing the activity of the superoxide dismutase (SOD) level and decreasing the concentration of malondialdehyde (MDA) in the jejunal mucosa. The licorice and rutin mixture altered the composition of intestinal microbiota by influencing the relative abundances of Bacteroidetes and Bacteroides. The relative abundances of the Bacteroidetes were significantly related to the laying rate of quails. In addition, the mixture of licorice and rutin was also effective in reducing the relative abundance of intestinal Proteobacteria and Enterobacter in quails, reducing the accumulation of antibiotic-resistance genes. The results revealed that supplementation of licorice and rutin mixture to the diet improved production performance, egg quality, and antioxidant capacity and modified the composition of intestinal microbiota in quails. This study provides a reference for Chinese herbal additives to promote production performance by modulating quail gut microbes.

Keywords: Quails; antioxidant capacity; gut microbiota; laying performance; licorice and rutin mixture.

Figure 1

The Alpha diversity between the control and treatment groups. (A) Chao1 index. (B) ACE index. (C) Shannon index. (D) Simpson index. *Indicates P < 0.05, **Indicates P < 0.01.

Figure 2

(A) Top 10 bacterial phyla of the cecum in all groups of quails; (B) top 10 bacterial genus of the cecum in all groups of quails.

Figure 3

Comparison of dominant intestinal microbiota at the phylum and genus level. Relative abundances of Bacteroidetes (A), Firmicutes (B), Proteobacteria (C), Actinobacteria (D), Bacteroides (E), Megamonas (F), Escherichia_shigella (G), and Prevotellaceae_UCG-001 (H).

Figure 4

Phylogenetic Investigation of communities by reconstruction of unobserved states (PICRUSt). (A, B) KEGG pathway annotation. (C) Level 2 in the term of cellular processes. (D) Level 3 in transport and catabolism.

Figure 5

Heatmap of the Spearman correlation analysis between the dominant microbial species and production performance (A), gut mucosa antioxidant parameters (B). The red represents a positive correlation and the blue represents a negative correlation, respectively (*P< 0.05), and (**P< 0.01). Abbreviations: ADFI, average daily feed intake; CAT, catalase; GSH-PX, glutathione peroxidase; MDA, malondialdehyde; SOD, superoxide dismutase.