Abstract: 【Objective】 This study was aimed to explore the effects of Clostridium perfringens (C.perfringens) infection on intestinal oxidative stress and inflammatory response in Yellow-feathered broilers,so as to lay a foundation for studying the pathogenesis of C.perfringens and developing prevention and control drugs.【Method】 A total of 100 one-day-old healthy Yellow-feathered broilers were randomly divided into 4 groups with 5 replicates per group and 5 broilers per replicate,namely control group and high,medium and low dose infection groups.During the whole period of the experiment,broilers were fed the basal diet.From 14 to 16 days of age,broilers in control group were fed with PBS,and broilers in high,medium and low dose infection groups were fed with 1×10⁹,1×10⁸ and 1×10⁷ CFU C.perfringens for 3 days,respectively.The blood biochemical indexes,oxidative stress and inflammation related factors in jejunum and ileum of broilers on 1 and 3 d post infection were measured,and the histopathological changes of jejunum and ileum were observed.【Result】 Compared with the control group,the inflammation-related factors and oxidative stress indicators in broilers in different dose infection groups showed different degrees of changes,in which the high-dose group significantly increased the activities of serum alkaline phosphatase (AKP),acid phosphatase (ACP),lactate dehydrogenase (LDH),as well as the content of malondialdehyde (MDA) in jejunum,the level of cytosolic interleukin (IL-8) in jejunum and ileum (P＜0.05),and decreased the activity of superoxide dismutase (SOD),the content of monocyte chemotactic protein (MCP-1) and cytosolic interleukin 10 (IL-10) in jejunum and ileum at 1 d post infection (P＜0.05).At 3 d post infection,the activities of AKP,ACP and LDH in serum of broilers infected with high dose increased significantly (P＜0.05),the contents of MDA,glutathione (GSH),tumor necrosis factor (TNF-α),MCP-1,IL-10,cysteine protease (caspase-1) and the relative expression levels of caspase-1,IL-1β,NOD-like receptor thermoprotein structural domain-associated protein 3 (NLRP3) mRNA in jejunum were significantly or extremely significantly increased (P＜0.05 or P＜0.01), and the contents of MDA,GSH,TNF-α,MCP-1,IL-1β,IL-8 and IL-10,as well as the relative mRNA expression levels of caspase-1,IL-1β,NLRP3 and Gasdermin A in ileum were significantly or extremely significantly increased (P＜0.05 or P＜0.01).The activity of AKP in serum and the activity of SOD in jejunum of broilers in the medium dose group were significantly increased at 1 d post infection (P＜0.05),and the activity of ACP and AKP in serum and GSH content in ileum were significantly increased at 3 d post infection (P＜0.05).The activities of ACP and AKP in serum of low dose group were significantly increased at both 1 and 3 d post infection post infection (P＜0.05),and the activity of SOD and the content of IL-18 in jejunum were significantly decreased at 1 d post infection (P＜0.05).In the high-dose group,the jejunum and ileum mucosa of broilers were bleeding,the epithelial cells of intestinal mucosa were necrotic and exfoliated,and inflammatory cells were infiltrating.The villi of jejunum and ileum in the middle and low dose groups were slightly broken,and the histological structure of jejunum and ileum in the control group was normal.【Conclusion】 1×10⁹ CFU Clostridium perfringens infected 14 day-old Yellow-feathered broilers for 3 consecutive days,might increase the expression of inflammatory factor in jejunum and ileum of chicks by activating NLRP3 inflammatory pathway,reduce the antioxidant level of chicks,cause intestinal pathological damage and induce chicken necrotizing enteritis.

Key words: Clostridium perfringens; Yellow-feathered broiler; oxidative stress; inflammatory factors; intestinal injury