Effects of Lagenaria siceraria (Molina) Standl polysaccharides on growth performance, immune function, cecum microorganisms and short-chain fatty acids in broilers

Abstract

In this study, Lagenaria siceraria (Molina) Standl polysaccharides (LSP) was prepared using the water-alcohol precipitation method to evaluate its effects on growth performance, slaughter performance, cytokines, immune organ indices, cecal short-chain fatty acids (SCFAs), and microbial community structure in broiler chickens when added to the basal diet. Seventy-five broiler chickens were selected and randomly divided into five groups, with 15 chickens per group. All groups were fed a basal diet for 7 days. From 7 days of age, the control group continued to receive the basal diet, while the positive drug group was fed a diet supplemented with Astragalus polysaccharides (APS, 100 g/kg) in addition to the basal diet. The experimental groups were fed diets containing different concentrations of LSP (50, 100, and 200 g/kg) in addition to the basal diet, and the supplementation continued for 42 days. The findings indicated that the incorporation of LSP into the feed significantly enhanced average daily weight gain (ADWG), average daily feed intake (ADFI), feed to gain ratio (F/G), dressing percentage, percentage of breast muscle, percentage of leg muscle, and percentage of abdominal fat while concurrently reducing drip loss rate and cooking loss rate (p < 0.01) in comparison to the control group. Additionally, it significantly augmented the levels of interleukin-4 (IL-4) and interleukin-12 (IL-12) in cytokines, secreted immunoglobulin A (SIgA) and immunoglobulin G (IgG) in immunoglobulins, as well as immune organ indicators (p < 0.05). Furthermore, LSP also modulated the intestinal microbiome composition by increasing the abundance of Bacteroides species and significantly changing concentrations of specific short-chain fatty acids (SCFAs) such as propionic acid, isobutyric acid, acetic acid, and isovaleric acid (p < 0.01). These results suggest that dietary supplementation with LSP can effectively regulate intestinal microbiome composition while promoting short-chain fatty acid production. The alterations in microbial characteristics ultimately contribute to improved intestinal immunity and immune organ development as well as enhanced production performance and immune function in broilers.

Keywords: Lagenaria siceraria (Molina) Standl polysaccharides; growth performance; immune function; intestinal microbiota; short-chain fatty acids.

Figure 1

Composition and structural analysis of LSP (A) Elution curve of LSP, (B) Fourier-transform infrared spectroscopy (FT-IR) analysis of LSP, (C) Mixed standard, (D) Monosaccharide composition of LSP. Numbers 1–6 represent xylose, arabinose, mannose, galactose, glucose, and rhamnose, respectively.

Figure 2

Repercussions of LSP on cytokine levels and immune organ indices. (A) IL-4 Content. (B) IL-5 Content. (C) IL-12 Content. (D) IFN-γ Content. (E) SIgA Content. (F) IgG Content. (G) Immunological organ index. Bars with different superscripts (A–D) indicate significant differences (p < 0.05).

Figure 3

Tissue section analysis results.

Figure 4

The influence of LSP on intestinal microbial abundance (A) Observed_species curve. (B) Shannon curve. (C) Rank abundance curve. (D) Venn diagram of ASVs/OTUs.

Figure 5

The impact of LSP on the diversity of intestinal microbiota (A) Grouped boxplot of alpha diversity indices. (B) Two-dimensional PCoA analysis plot. (C) Two-dimensional NMDS plot.

Figure 6

The influence of LSP on the composition of microbial communities. (A) bar plot of phylum-level species composition. (B) Bar plot of genus-level species composition. (C) Intergroup differences in taxonomic units based on classification tree. (D) Bar plot of LDA effect sizes for indicator species.