Alterations in Intestinal Antioxidant and Immune Function and Cecal Microbiota of Laying Hens Fed on Coated Sodium Butyrate Supplemented Diets

Abstract

This study was designed to evaluate the effects of dietary coated sodium butyrate (CSB) on the intestinal antioxidant, immune function, and cecal microbiota of laying hens. A total of 720 52-week-old Huafeng laying hens were randomly allocated into five groups and fed a basal diet supplemented with CSB at levels of 0 (control), 250 (S250), 500 (S500), 750 (S750), and 1000 (S1000) mg/kg for eight weeks. The results revealed that CSB supplementation quadratically decreased the malondialdehyde content and increased the superoxide dismutase activity of the jejunum as well as the total antioxidative capacity activity of the ileum (p < 0.05). Dietary CSB supplementation linearly decreased the diamine oxidase and D-lactic acid content of the serum (p < 0.05). Compared with the control group, the addition of CSB resulted in linear and/or quadratic effects on the mRNA expression of inflammatory cytokines TNF-α, IL-6, and IL-10 in the jejunum and ileum (p < 0.05). The short-chain fatty acid concentrations increased quadratically as supplemental CSB improved (p < 0.05). Additionally, dietary CSB levels had no effect on microbial richness estimators, but ameliorated cecal microbiota by raising the abundance of probiotics and lowering pathogenic bacteria enrichment. In conclusion, our results suggest that dietary supplementation with CSB could improve the intestinal health of laying hens via positively influencing the antioxidant capacity, inflammatory cytokines, short-chain fatty acids, and gut microbiota. In this study, 500 mg/kg CSB is the optimal supplement concentration in the hens’ diet.

Keywords: cecal microbiota; coated sodium butyrate; immune function; laying hens.

Figure 1

Effects of dietary CSB treatment on antioxidase changes in jejunum and ileum (n = 6). ^a,b Means with different superscripts within a column differ significantly (p < 0.05). T-AOC: total antioxidant capacity; CAT: catalase; SOD: superoxide dismutase; MDA: malondialdehyde.

Figure 2

Effects of dietary CSB levels on serum biochemical indices (n = 6). ^a,b Means without common letters above the histogram differ significantly (p < 0.05). DAO: Diamine oxidase, DL: D-lactic acid, TBA: Total bile acid.

Figure 3

mRNA expression levels of inflammatory cytokines in the jejunum and ileum of laying hens (n = 6). ^a–c Means with different superscripts within a column differ significantly (p < 0.05). TNF-α: Tumor necrosis factor-alpha; IL-1β: interleukin-1 beta; IL-6: interleukin-6; IL-10: interleukin-10.

Figure 4

Cecum SCFAs contents of laying hens (n = 6). ^a–c Means with different superscripts within a column differ significantly (p < 0.05).

Figure 5

Correlation heatmap (a) and Correlation network (b) between SCFAs and inflammatory cytokines, and antioxidant indexes in the jejunum; Correlation heatmap (c) and Correlation network (d) between SCFAs and inflammatory cytokines, and antioxidant indexes in the ileum. * p < 0.05 and ** p < 0.01.

Figure 6

The microbial beta diversity was assessed by principal component analysis (PCA), principal coordinate analysis (PCoA), and nonmetric multidimensional scaling (NMDS) analysis based on the OTU table.

Figure 7

Microbial composition and significant differential bacteria in the cecum of laying hens at the phylum level (a), class level (b), and family level (c). Statistical differences between the two groups were calculated by Student’s t-test with Welch’s correction. * p < 0.05 and ** p < 0.01.

Figure 7

Microbial composition and significant differential bacteria in the cecum of laying hens at the phylum level (a), class level (b), and family level (c). Statistical differences between the two groups were calculated by Student’s t-test with Welch’s correction. * p < 0.05 and ** p < 0.01.

Figure 8

LEfSe (a) and LDA (b) analyses based on OTUs characterized the microbiomes of the control and S500 groups.