Glycerol Monolaurate Attenuated Immunological Stress and Intestinal Mucosal Injury by Regulating the Gut Microbiota and AMPK/NF-κB/Nrf2 Signaling Pathway in Lipopolysaccharide-Challenged Broilers

Background Antibiotic residues and resistance issues have led to the ban on antibiotic growth promoters in the poultry industry. Targeted dietary supplementation such as glycerol monolaurate (GML) has been found to ameliorate the negative effects of restriction on the use of antibiotic growth promoters by modulating the animal immune system and intestinal health. However, the mechanism by which GML contributes to the health and growth of broilers is indistinct. This study was conducted to investigate the effects of GML on immunity, intestinal barrier function, and cecal microbiota profiles in lipopolysaccharide (LPS)-challenged broilers. Results The results revealed that dietary GML intake augmented serum immunoglobulin A and G levels in LPS-challenged broilers. GML supplementation normalized LPS-induced variations in serum interleukin-6, interferon-γ, and LPS levels; jejunal villus height; and gene expression of interleukin-6, macrophage inflammatory protein-3α, toll-like receptor 4, nuclear factor kappa-B (NF-κB), caspase-1, tight junction proteins, adenosine monophosphate-activated protein kinase α1, nuclear factor-erythroid 2-related factor 2, and superoxide dismutase-1. GML administration ameliorated LPS-induced peroxidation by reducing malondialdehyde content and increasing antioxidant enzyme activity. Dietary GML intake enhanced the abundances of cecal probiotics such as Blautia, Lactobacillus, and Coprobacter in challenged broilers. The LPS-induced reduction in Anaerostipes, Pseudoflavonifractor, and Gordonibacter abundances in the cecum was inhibited by GML supplementation. Dietary GML intake was positively correlated with alterations in antioxidant enzyme activities and adenosine monophosphate-activated protein kinase (AMPK) α1, nuclear factor-erythroid 2-related factor 2 (Nrf2), and zonula occludens-1 levels. The genera Anaerostipes, Lachnospira, Gordonibacter, Lachnospira, Marvinbryantia, Peptococcus, and Pseudoflavonifractor were linked to attenuated inflammation and improved immunity and antioxidant capacity of LPS-challenged broilers. Conclusion Dietary GML intake alleviated LPS-induced immunological stress and intestinal injury in broilers. This beneficial effect of GML supplementation was attributed to the suppression of inflammation and oxidative stress by regulation of cecal microbiota and the AMPK/NF-κB/Nrf2 signaling pathway in LPS-challenged broilers.

Novel Gut Microbiota Patterns Involved in the Attenuation of Dextran Sodium Sulfate-Induced Mouse Colitis Mediated by Glycerol Monolaurate via Inducing Anti-inflammatory Responses

The gut microbiota, which can be highly and dynamically affected by dietary components, is closely related to IBD pathogenesis. Here, we demonstrated that food-grade glycerol monolaurate (GML)-mediated enhancement of Bifidobacterium and fecal SCFAs could be responsible for the anticolitis effect.

Effect of supplemental glycerol monolaurate and oregano essential oil blend on the growth performance, intestinal morphology, and amino acid digestibility of broiler chickens

Background This experiment tested the impact of the combined supplementation of glycerol monolaurate (GLM) and oregano essential oil (EO) to broiler diets. Growth performance, metabolic response, immune status, apparent ileal digestibility coefficient (AID%), and intestinal histomorphology were assessed. Three-day-old Ross-308 broilers (76.62 g ± 0.50, n = 240) were randomly allocated into 4 experimental groups (6 replicates/group and 10 chicks/replicate). Birds were fed corn-soybean meal basal diets supplemented with four levels of GLM and oregano EO blend: 0, 0.15, 0.45, and 0.75% for 35 days. Results During the starter period, dietary GLM and oregano EO did not show significant (P > 0.05) changes in growth performance. During the grower period, GLM and oregano EO supplemented groups showed a linear and quadratic decline in FCR. During the finisher and overall performance, a linear increase in the body weight (BW), body weight gain (BWG), the protein efficiency ratio (PER), and relative growth rate (RGR), and a linear decrease in the FCR at 0.75% dietary level of GLM and oregano EO compared to the control. The broken-line regression model showed that the optimum dietary level of GLM and oregano EO blend was 0.58% based on final BW and FCR. The 0.45% or 0.15% dietary level of supplemented additives lowered (P < 0.05) the AID% of threonine and arginine, respectively, with no change in the AID% of other assessed amino acids at all dietary levels. Muscle thickness in jejunum and ileum in all dietary supplemented groups was increased (P < 0.05); however, such increase (P < 0.05) in the duodenum was shown at 0.45 and 0.75% dietary levels. All GLM and oregano EO supplemented groups showed increased (P < 0.05) duodenal, jejunal, and ileal villus height. The 0.15 and/or 0.75% dietary levels of supplemented additives increased (P < 0.05) the ileal and duodenal crypt depth, respectively, with a decreased (P < 0.05) duodenal crypt depth at 0.15% dietary level. The goblet cell count in ileum decreased (P < 0.05) in all GLM and oregano EO supplemented groups, but this decreased count (P < 0.05) was detected in jejunum at 0.45 and 0.75% dietary levels. The GLM and oregano EO supplemented groups did not show significant (P > 0.05) changes in the assessed metabolic and immune status parameters. Economically, the total return and performance index was increased at 0.75% dietary level. Conclusion Better growth performance was achieved at a 0.75 % dietary level of GLM and oregano EO by improving most intestinal morphometric measures. The optimum dietary level detected was 0.58%. The lack of influence of supplemented additives on chickens' immune and metabolic responses could indicate a lack of synergy between GLM and oregano EO.

Glycerol Monolaurate Ameliorated Intestinal Barrier and Immunity in Broilers by Regulating Intestinal Inflammation, Antioxidant Balance, and Intestinal Microbiota

This study was conducted to investigate the impact of glycerol monolaurate (GML) on performance, immunity, intestinal barrier, and cecal microbiota in broiler chicks. A total of 360 one-day-old broilers (Arbor Acres) with an average weight of 45.7 g were randomly allocated to five dietary groups as follows: basal diet and basal diets complemented with 300, 600, 900, or 1200 mg/kg GML. Samples were collected at 7 and 14 days of age. Results revealed that feed intake increased (P &lt; 0.05) after 900 and 1200 mg/kg GML were administered during the entire 14-day experiment period. Dietary GML decreased (P &lt; 0.05) crypt depth and increased the villus height-to-crypt depth ratio of the jejunum. In the serum and jejunum, supplementation with more than 600 mg/kg GML reduced (P &lt; 0.05) interleukin-1β, tumor necrosis factor-α, and malondialdehyde levels and increased (P &lt; 0.05) the levels of immunoglobulin G, jejunal mucin 2, total antioxidant capacity, and total superoxide dismutase. GML down-regulate (P &lt; 0.05) jejunal interleukin-1β and interferon-γ expression and increased (P &lt; 0.05) the mRNA level of zonula occludens 1 and occludin. A reduced (P &lt; 0.05) expression of toll-like receptor 4 and nuclear factor kappa-B was shown in GML-treated groups. In addition, GML modulated the composition of the cecal microbiota of the broilers, improved (P &lt; 0.05) microbial diversity, and increased (P &lt; 0.05) the abundance of butyrate-producing bacteria. Spearman’s correlation analysis revealed that the genera Barnesiella, Coprobacter, Lachnospiraceae, Faecalibacterium, Bacteroides, Odoriacter, and Parabacteroides were related to inflammation and intestinal integrity. In conclusion, GML ameliorated intestinal morphology and barrier function in broiler chicks probably by regulating intestinal immune and antioxidant balance, as well as intestinal microbiota.

Glycerol monolaurate ameliorated intestinal barrier and immunity in broilers by regulating intestinal inflammation, antioxidant balance, and intestinal microbiota

Extensive interactions occur between a poultry host and its gut microbiome. Glycerol monolaurate (GML) possesses a large range of antimicrobial and immunoregulatory properties. This study was conducted to investigate the impact of different doses of GML (basal diets complemented with 0, 300, 600, 900, or 1200 mg/kg GML) on growth performance, intestinal barrier, and cecal microbiota in broiler chicks. Results revealed that feed intake increased after 900 and 1200 mg/kg GML were administered during the entire 14-day experiment period. Dietary GML decreased crypt depth and increased the villus height-to-crypt depth ratio of the jejunum. In the serum and jejunum, supplementation with more than 600 mg/kg GML reduced interleukin-1β, tumor necrosis factor-α, and malondialdehyde levels and increased the levels of immunoglobulin G, jejunal mucin 2, total antioxidant capacity, and total superoxide dismutase. GML down-regulated jejunal interleukin-1β and interferon-γ expression and increased the mRNA level of zonula occludens 1 and occludin. A reduced expression of toll-like receptor 4 and a tendency of down-regulated nuclear factor kappa-B was shown in GML-treated groups. In addition, GML modulated the composition of the cecal microbiota of the broilers, improved microbial diversity, and increased the abundance of butyrate-producing bacteria. Spearman's correlation analysis revealed that the genera Barnesiella, Coprobacter, Lachnospiraceae, Faecalibacterium, Bacteroides, Odoriacter, and Parabacteroides were related to inflammation and intestinal integrity. In conclusion, GML ameliorated intestinal morphology and barrier function in broiler chicks probably by regulating intestinal immune and antioxidant balance, as well as intestinal microbiota.