Effects Of Lactobacillus Plantarum On Intestinal Morphology And Immune Responses Of Chickens Infected With Clostridium Perfringens Under Different Environment

In our study,we aim to explore the protective effect of Lactobacillus plantarum supplementation on Clostridium perfringens infected chickens in two environments（the specific pathogen free environment and free-range system environment）.The experiment used a 2×2 two-factor design method,and selected 80 1-day-old White Leghorn laying hens of similar weight to be randomly divided into 4 groups:free-range environment+basic diet group,free-range environment+Lactobacillus plantarum group,specific pathogen-free（SPF）environment+basic diet group,SPF environment+Lactobacillus plantarum group.Lactobacillus plantarum was added to the diet of laying hens aged 1-35days in two environments,all laying hens were in 36-42 days old oral administration of 1m L of Clostridium perfringens per day,sampling on 1^st、3^rd、10^th days after challenged,the entire test period was 52 days.By comparing the structural integrity of the small intestine of laying hens,serum biochemical and immune indicators,and the expression results of ileal cytokines and tight junction proteins of laying hens,the protective effects of environment and Lactobacillus plantarum on Clostridium perfringens challenged laying hens were analyzed.The results showed that the Clostridium perfringens administration led to visible and histomorphological gut lesions,and the free-range environment can significantly increase the height of ileal villi in egg-laying chickens challenged by Clostridium perfringens.In the specific pathogen free or free-range system environment,dietary supplementation with Lactobacillus plantarum obvious increased the ratio of intestinal villus height to crypt depth and the expression of MUC2 m RNA in ileum mucosa,then reduced the m RNA expression level of TNF-αgene in the ileum mucosa.Lactobacillus plantarum treatment significantly reduced the contents of total protein,total superoxide dismutase and glutamic oxaloacetic transaminase in serum of the chickens.Based on the results,the free-range system environment contributed to the repair of damage in the later stages of chicken inflammation.We believe that Lactobacillus plantarum supplementation in the free-range system environment is more conducive to the recovery of Clostridium perfringens infection in chickens.