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

This study was conducted to investigate the effects of glycerol monolaurate (GML) on lipopolysaccharide (LPS)-induced immunological stress and intestinal mucosal injury in broilers and its underlying mechanisms. A total of 144 one-d-old Arbor Acres broilers were allocated to a 2 × 2 factorial arrangement involving dietary treatment (0 or 1,200 mg/kg dietary GML) and LPS challenge (injected with saline or LPS on d 16, 18, and 20). Samples were collected on d 21. The results revealed that dietary GML augmented serum immunoglobulin A ( = 0.009) and immunoglobulin G ( < 0.001) levels in challenged birds. Dietary GML normalized LPS-induced variations in serum interleukin-6, interferon-gamma, and LPS levels ( < 0.05), jejunal villus height ( = 0.030), and gene expression of interleukin-6, macrophage inflammatory protein-3 alpha, Toll-like receptor 4, nuclear factor kappa-B, caspase-1, tight junction proteins, adenosine monophosphate-activated protein kinase alpha 1 (), nuclear factor-erythroid 2-related factor 2 (), and superoxide dismutase-1 ( < 0.05). GML supplementation ameliorated LPS-induced peroxidation by reducing malondialdehyde content and increasing antioxidant enzyme activity ( < 0.05). Dietary GML enhanced the abundances of , , and and reduced the proportion of in challenged birds. Dietary GML was positively correlated with alterations in antioxidant enzyme activities and , , and zonula occludens-1 expressions. The genera , , , , , , and were linked to attenuated inflammation and improved antioxidant capacity of challenged birds. In conclusion, dietary GML alleviated LPS-induced immunological stress and intestinal injury of broilers by suppressing inflammation and oxidative stress. Dietary GML regulated cecal microbiota and activated the AMPK/Nrf2 pathway in LPS-challenged broilers.