Chlorogenic acid protects against intestinal inflammation and injury by inactivating the mtDNA–cGAS–STING signaling pathway in broilers under necrotic enteritis challenge

ABSTRACT This study aimed to determine the effects of chlorogenic acid ( CGA ) on the growth performance, intestinal health, immune response, and mitochondrial DNA ( mtDNA )–cyclic GMP–AMP synthase ( cGAS )–stimulator of interferon genes ( STING ) signaling pathway in broilers under necrotic enteritis ( NE ) challenge. The 180 one-day-old male Cobb 500 broilers with similar body weight of 44.59 ± 1.39 g were randomly allocated into three groups. The groups were control diet (Control group), control diet + NE challenge (NE group), and control diet + 500 mg/kg CGA + NE challenge (NE + CGA group), with six replicates per treatment. All broilers except the Control group were given sporulated coccidian oocysts (day 14) and Clostridium perfringens (days 19-21) by oral gavage. Our findings showed that CGA improved the growth performance and intestinal morphology in broilers under NE challenge. CGA supplementation elevated the barrier function in broilers under NE challenge, which reflected in the decreased serum concentrations of D-lactate and diamine oxidase, and upregulated jejunal protein expression of occludin. CGA supplementation also improved the immune function, which reflected in the increased concentrations and gene expressions of anti-inflammatory factors, and decreased concentrations and gene expressions of pro-inflammatory factors. CGA supplementation further enhanced intestinal cell proliferation and differentiation, which manifested in the increased number of goblet cells and positive cells of proliferating cell nuclear antigen on days 28 and 42. Furthermore, CGA supplementation decreased the mtDNA (day 42) and mitochondrial reactive oxygen species levels (days 28 and 42), and increased the mitochondrial membrane potential (day 42) and mitochondrial complex Ⅰ (days 28 and 42) or Ⅲ (day 28) activity. Broilers challenged with NE had upregulated jejunal protein expressions of cGAS, phospho-TANK-binding kinase 1, and phospho-interferon regulatory factor 7 compared with the Control group, which were downregulated after CGA supplementation. In conclusion, dietary supplementation CGA could protect against intestinal inflammation and injury by reducing the leakage of mtDNA and inactivating the cGAS–STING signaling pathway in broilers under NE challenge.