The modulatory effects of alfalfa polysaccharide on intestinal microbiota and systemic health of Salmonella serotype (ser.) Enteritidis-challenged broilers

Abstract

Salmonella serotype (ser.) Enteritidis infection in broilers is a main foodborne illness that substantially threatens food security. This study aimed to examine the effects of a novel polysaccharide isolated from alfalfa (APS) on the intestinal microbiome and systemic health of S. ser. Enteritidis-infected broilers. The results indicated that broilers receiving the APS-supplemented diet had the improved (P < 0.05) growth performance and gut health than those fed no APS-supplemented diet. Supplementation with APS enhanced (P < 0.05) the richness of gut beneficial microbes such as Bacteroidetes, Barnesiella, Parabacteroides, Butyricimonas, and Prevotellaceae, while decreased (P < 0.05) the abundance of facultative anaerobic bacteria including Proteobacteria, Actinobacteria, Ruminococcaceae, Lachnospiraceae, and Burkholderiaceae in the S. ser. Enteritidis-infected broilers. The Bacteroides and Odoribacter were identified as the two core microbes across all treatments and combined with their syntrophic microbes formed the hub in co-occurrence networks linking microbiome structure to performance of broilers. Taken together, dietary APS supplementation improved the systemic health of broilers by reshaping the intestinal microbiome regardless of whether S. ser. Enteritidis infection was present. Therefore, APS can be employed as a potential functional additives to inhibit the S. ser. Enteritidis and enhance the food safety in poultry farming.

Influence of the ecological environment on the structural characteristics and bioactivities of polysaccharides from alfalfa (Medicago sativa L.)

“…Plant-derived polysaccharides (PS) are a kind of macromolecular polymer synthesized in plants, which plays many vital roles in maintaining the integrity of cells and in imparting resistance against abiotic stress in plants. 1,2 As a functional food/ feed for humans and animals, phytogenic PS exhibit a variety of bioactivities, 3,4 including antioxidative capacity, 5,6 antiinflammation, 7,8 immunomodulation, 9 and growth-promotion. 10 Homogeneous PS are composed of a single kind of monomer by glycosidic bonding, whereas hetero-PS comprise polymers of several kinds of monosaccharides or uronic acids.…”

Plant-Derived Polysaccharides Regulated Immune Status, Gut Health and Microbiota of Broilers: A Review

“…Dietary Achyranthes bidentata polysaccharide supplementation increased body weight and average daily weight gain of broilers challenged with Escherichia coli K88 (14). It was also reported that Salmonella serotype Enteritidis-infected broilers exhibited impaired growth performance, but this was relieved by diets supplemented with polysaccharides isolated from alfalfa (24). Additionally, the biological activities of polysaccharides are closely related to their molecular weight and specific spatial structures (25).…”

“…Polysaccharide supplementation decreased the content of D-lactic acid and the activity of diamine oxidase in the serum, implying that polysaccharides improved the intestinal permeability and protected the intestinal barrier function (35). Accordingly, accumulated evidences showed that polysaccharides improved the intestinal integrity, maintained the integrity of intestinal epithelium, and upregulated mRNA expressions or protein abundances of tight junction proteins such as ZO-1, occludin, and claudin-1 in the jejunum and ileum of broilers in normal or stressed conditions (12,24,44). It was generally reported that polysaccharides could not be absorbed through the intestinal mucosa into the body, so the health benefits of polysaccharides were rooted in their effects on the intestinal mucosal immune system (49).…”

“…Therefore, the reasons for maintaining the integrity of intestinal mucosa by polysaccharides could be speculated as follows: First, polysaccharides improved the proliferation and maturation of intestinal epithelial cells to regulate the intestinal immune functions by synthesizing and releasing mucins, and enhancing the integrity of intestinal mucosa (42,53). Second, a diet supplemented with polysaccharides is beneficial in promoting the development of IgA-producing cells in the intestinal mucosa and increasing the production of secretory immunoglobulin A, which is a major antibody isotype in the intestinal mucosal immunity that can prevent pathogens and toxins from invading the epithelial surface, and maintain the homeostasis of the intestine (24,42,54). Additionally, the protective effects of polysaccharides on the intestinal mucosa barrier were partly associated with its anti-inflammatory effects (12,55).…”

Progress of Studies on Plant-Derived Polysaccharides Affecting Intestinal Barrier Function in Poultry

“…Except for the above normal feeding conditions, plant-derived polysaccharides could also play a role in poultry under challenging conditions such as pathogen growth. When broilers are infected with Salmonella serotype resulting in enteritis, a dietary addition of 500 mg/kg alfalfa polysaccharides enhanced the abundance of beneficial microorganisms in the intestinal tract, such as Bacteroides , Barnesiella , Parabacteroides , Butyricimonas , Prevotellaceae while decreasing facultative anaerobic bacteria, including Proteobacteria , Actinomycetes , Ruminococcaceae , Lachnospiraceae and Burkholdeaceae [ 34 ]. Moreover, Cui et al [ 35 ] found that dietary Caulis Spatholobi polysaccharide (0.2, 0.4, and 0.6%) increased cecum species richness, restored cyclophosphamide-induced intestinal microbiota imbalance, and improved Lactobacillus abundance.…”