Abstract:Constipation is a common gastrointestinal disorder. Some Bifidobacterium animalis subsp. lactis has been shown to have an ameliorative effect on constipation, but there is variation in their effectiveness. In order to investigate the effect of different B. lactis strains on constipation, an animal model of constipation was established, and the constipation-related indexes, gut microbiota and their metabolite levels were determined through the intervention experiments of three B. lactis strains, to investigate the effects of constipation alleviation of the strains and their mechanisms. The results showed that CCFM1278 and BB12 significantly improved the weight of defecation, number of fecal pellets, fecal water content, time to first black stool, and small intestinal propulsion rate in constipated mice, while the effect of FJSSZ6M5 was not significant. B. lactis CCFM1278 modulated the relative abundance of Akkermansia, Ruminiclostridium 6, Ruminococcus 1 and Alloprevotella in the gut microbiota of constipated mice, improved the abnormal levels of short-chain fatty acids and deoxycholic acid, significantly improved the secretion of gastrin and somatostatin and inhibited the expression of aquaporin 3 and aquaporin 8. In conclusion, B. lactis CCFM1278 has the potential to relieve constipation. This study provides a new direction for the treatment of patients with constipation.