Bacillus amyloliquefaciens Regulates the Keap1/Nrf2 Signaling Pathway to Improve the Intestinal (Caco-2 Cells and Chicken Jejunum) Oxidative Stress Response Induced by Lipopolysaccharide (LPS)

This article aims to investigate the mechanism by which alleviates lipopolysaccharide (LPS)-induced intestinal oxidative stress. The study involved two experimental subjects: human colorectal adenocarcinoma (Caco-2) cells and Arbor Acres broiler chickens. The experiment involving two samples was designed with the same treatment groups, specifically the control (CK) group, lipopolysaccharide (LPS) group, (JF) group, and JF+LPS group. In the Caco-2 experiment, we administered 2 μg/mL of LPS and 1 × 10 CFU/mL of JF to the LPS and JF groups, respectively. In the broiler experiment, the LPS group (19-21 d) received an abdominal injection of 0.5 mg/kg BW of LPS, whereas the JF group was fed 1 × 10 CFU/g of JF throughout the entire duration of the experiment (1-21 d). The results indicated the following: (1) JF significantly decreased the DPPH free radical clearance rate and hydrogen peroxide levels ( < 0.05). (2) JF significantly enhanced the total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH Px) activity in Caco-2 cells ( < 0.05), while concurrently reducing malondialdehyde (MDA) content ( < 0.05). (3) Compared to the CK group, JF significantly increased the mRNA expression levels of ( ), ( ), SOD, ( ), GSH-Px, ( ), ( ), Claudin, Occludin1, ( ), and ( ) in Caco-2 cells ( < 0.05), while concurrently reducing the mRNA expression of ( ), ( ), ( ), and ( ) ( < 0.05). In comparison to the LPS group, the JF+LPS group demonstrated a significant increase in the mRNA expression of , , , and , as well as , , and in Caco-2 cells ( < 0.05), alongside a decrease in the mRNA expression of , , and ( < 0.05). (4) In broiler chickens, the JF group significantly elevated the levels of T-AOC, CAT, and GSH-Px in the jejunum while reducing MDA content ( < 0.05). Furthermore, the CAT level in the JF+LPS group was significantly higher than that observed in the LPS group, and the levels of MDA, TNF-α, and IL-1β were significantly decreased ( < 0.05). (5) In comparison to the CK group, the JF group exhibited a significant increase in levels in the jejunum of broiler chickens ( < 0.05). Notably, the mRNA expression levels of , , , , , and were reduced ( < 0.05), while the mRNA expression levels of , and also showed a decrease ( < 0.05). Furthermore, the mRNA expression levels of , , , and in the JF+LPS group were significantly elevated compared to those in the LPS group ( < 0.05), whereas the mRNA expression levels of and were significantly d