The Impact of Probiotic Intervention on the Gut Microbiota and Bowel Function

Inclusion Criteria: 1. Age between 18 and 75 years 2. Ultra low rectal cancer meeting the indication for Intersphincteric Resection (ISR) surgery 3. Underwent a prophylactic ileostomy 4. Scheduled for stoma reversal surgery within 6 months after the ISR procedure 5. Digestive tract reconstruction achieved via either hand-sewn or stapled coloanal anastomosis 6. Patient has a strong preference for undergoing sphincter-preserving surgery 7. Capable of understanding and willing to provide signed informed consent Exclusion Criteria: 1. Does not meet the surgical indications for Intersphincteric Resection (ISR) 2. Presence of multiple primary colorectal malignancies 3. Patients who have received neoadjuvant radiotherapy 4. Patients who experience disease progression or death in the postoperative period 5. Patients who develop severe anastomotic complications postoperatively, such as anastomotic leakage or stenosis 6. Patients whose actual stoma reversal surgery occurs more than 6 months after the ISR procedure 7. Patients who require long-term(more than 3 months) use of antibiotics 8. History of allergy to Clostridium butyricum (live) Tablets (MIYA) or any of its components 9. Concurrent use of other probiotic during the study period 10. Coexisting inflammatory bowel disease 11. History of neurological or psychiatric disorders, including but not limited to Parkinson's disease, Alzheimer's disease, organic brain diseases, stroke, epilepsy, or major psychiatric disorders (e.g., major depressive disorder) 12. Pregnant or lactating women