Abstract: 【Objective】 The experiment was to explore the effects of compound organic acids on growth performance,intestinal morphology and cecal microflora of broilers infected with Clostridium perfringens.【Method】 Sixty one-day-old Sanhuang chickens were randomly divided into 6 treatment groups with 10 chickens in each group,which were blank control group (BC), Clostridium perfringens model group (P),positive drug (lincomycin) treatment group (PT) and 10,20 and 40 mg/kg compound organic acid treatment groups (L,M and H),respectively.At 1 day of age,except BC group,broilers in other groups were gavage 1.5×10⁸ CFU Clostridium perfringens for 7 d.Simultaneously,broilers in PT group was gavage with 1 mL lincomycin for 7 d，and broilers in L,M and H groups were intragastrically given 1 mL of compound organic acids with corresponding concentration for 7 d.Broilers in BC group were given 1 mL normal saline intragastrically,and the experiment lasted for 13 d.The change of body weight and remaining feed amount of broilers were recorded every day during the experiment,and feed to gain ratio was calculated.On the 13th day,duodenum,jejunum and ileum of broilers in each group were collected,intestinal tissue morphology was determined,and cecal contents were collected for cecal microbial 16S rRNA sequencing analysis.【Result】 ①Compared with BC group,the average daily gain and average daily feed intake of broilers in P group were decreased,and the feed to gain ratio was increased (P＞0.05).Compared with P group,the average daily gain of broilers in PT,L,M and H groups was increased and the feed to gain ratio was decreased (P＞0.05).With the increase of compound organic acid dose,the average daily gain of broilers in L,M and H groups showed an increasing trend. ②Compared with BC group,villus height and V/C value of duodenum,jejunum and ileum of broilers in P group were significantly decreased (P＜0.05).Compared with P group,the villus height of duodenum,jejunum and ileum of broilers in PT,L,M and H groups was significantly increased (P＜0.05),and the V/C value of duodenum and jejunum was significantly increased (P＜0.05).The villus height and V/C value of duodenum of broilers in H group were the highest,and significantly higher than those in other groups (P＜0.05).③The results of sequencing analysis showed that 76 OTUs were obtained from cecal contents samples of the 6 groups,including 62 common core OTUs,and the unique OTUs of BC,PT,L,M and H groups were 5,2,1,1 and 5,respectively.The diversity of cecal microflora of broilers in P group was lower,and the diversity and demeanor of cecal microflora of broilers in H group were the highest,and the species abundance was also the highest.④ Compared with BC group,the ratio of Bacteroidetes to Firmicutes of cecal microorganisms in P group was increased (P＞0.05).Compared with P group,the ratio of Bacteroidetes to Firmicutes of cecal microorganisms in H group was increased (P＞0.05).【Conclusion】 Compound organic acids could prevent the development of intestinal lesions in necrotic enteritis caused by Clostridium perfringens infection.Under the conditions of this experiment,40 mg/kg compound organic acids had the best therapeutic effect.

Key words: necrotic enteritis; compound organic acid; Clostridium perfringens