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

Chuanpi Xiao,Zhigang Song,Zhenhua Wang,Linglian Kong,Qidong Zhu

doi:10.3389/fimmu.2021.713485

Abstract

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 < 0.05) after 900 and 1200 mg/kg GML were administered during the entire 14-day experiment period. Dietary GML decreased (P < 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 < 0.05) interleukin-1β, tumor necrosis factor-α, and malondialdehyde levels and increased (P < 0.05) the levels of immunoglobulin G, jejunal mucin 2, total antioxidant capacity, and total superoxide dismutase. GML down-regulate (P < 0.05) jejunal interleukin-1β and interferon-γ expression and increased (P < 0.05) the mRNA level of zonula occludens 1 and occludin. A reduced (P < 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 < 0.05) microbial diversity, and increased (P < 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.

Highlights

Antibiotics play a significant role in disease prevention and growth promotion in the poultry industry
The administration of 900 and 1200 mg/kg glycerol monolaurate (GML) increased feed intake (FI) compared to the control and 300 mg/kg GML-treated group during the overall period
To initially evaluate the effect of dietary GML on immune response status, the levels of interleukin 1 beta (IL-1b), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-a), and immunoglobulin G (IgG) in the serum were estimated by ELISA (Table 4)

Summary

Introduction

Antibiotics play a significant role in disease prevention and growth promotion in the poultry industry. Targeted dietary supplementation or using a feed additive may be useful in the immunomodulation of the immune system. These ingredients can reduce the negative impacts of environmental stressors on animal immune systems and production performance [3]. Extensive research has been carried out to evaluate an array of products as alternatives to antibiotic growth promoters; such products, including food industry by-products, plant metabolites, non-digestible oligosaccharides, natural byproducts, essential minerals, amino acids, medicinal herbs, organic acids, and essential oils, can at least partially alter immune function in poultry [2]

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