IL17A and colitis: Continuous L. paracasei 207-27 administration perpetuated the promotion of gut barrier but showed no anti-colitis function, which is likely because the continued use of single-strain stimulation after antibiotic exposure is unhelpful in gut microbiota diversity restoration; therefore, it was inferior to the 207-27 short-term group in systemic immunity, such as splenic IL-5, IL-6, and serum IL-17A levels.