Melatonin alleviates necrotizing enterocolitis by reducing bile acid levels through the SIRT1/FXR signalling axis

•The serum and fecal bile acid profiles of NEC mice are characterized.•The elevation of bile acid levels in NEC is associated with the impairment of enterohepatic circulation.•Melatonin effectively restores FXR functionality in bile acid regulation by suppressing acetylation.•Melatonin alleviates NEC by reducing bile acid levels, supporting its clinical use.