After the rabbits were slaughtered, the jejunum and ileum were placed in 1.5 mL cryopreservation tubes, and stored at 80 C. The contents of interleukin-2 (IL-2), interleukin-10 (IL-10), secretory immunoglobulin A (SIgA), secretory immunoglobulin G (SIgG), and tumour necrosis factor-a (TNF-a) in the jejunum and ileum were measured in samples from each group. The detection method is carried out according to the method of Li et al. (2020). The Elisa kits were provided by Shanghai Hengyuan Biological Co., Ltd. (Shanghai, China).