The Interactive Effect Of Dietary Deoxynivalenol And Clostridium Perfringens Challenge On The Gut Health Of Broiler Chickens

Deoxynivalenol is one of the most serious mycotoxin contamination in crops and animal feeds that could induce necrosis of intestinal mucous layer,diarrhea,vomit,decreased feed conversion and impaired immune function.Clostridium perfringens,the pathogenic agent of necrotic enteritis exist in environment and the intestine of human and broiler chickens.With the change of climate and the limited use of antibiotic,the detection rate of deoxynivalenol and the morbidity of Clostridium perfringens become higher,and the co-occurrence of deoxynivalenol and Clostridium perfringens happens occasionally.In this study,we investigate the effect of dietary deoxynivalenol and Clostridium perfringens challenge on the gut health on broiler chickens and their reactive effect,trying to supply theoretical foundation on the treatment of dietary deoxynivalenol contamination and Clostridium perfringens challenge.Exp.1 The interactive effect of dietary deoxynivalenol and Clostridium perfringens challenge on the development of immune organs and the intestinal absorptive function of broiler chickensIn a 2×2 factorial arrangement,a total of 120 one-day-old chicks(AA)with similar body weight from a commercial hatchery were randomly divided into 4 groups consisting of6 replicates with 5 birds per replicate.1)Birds of group CON were fed basal diet;2)Birds of group DON were fed basal diet contaminated with deoxynivalenol at 5mg per kg diet;3)Birds of group CP were challenged with Clostridium perfringens culture medium at 8×10~8cfu/m L,and the dose was l m L per day per bird from day 17 to 20;4)Group DC fed basal diet contaminated with 5 mg DON per kg diet and challenged with Clostridium perfringens medium at 8×10~8cfu/m L,and the dose was l m L per day per bird from day 17 to 20.The results showed that dietary deoxynivalenol and Clostridium perfringens challenge had no effect on the development of liver,spleen,thymus and bursa of broiler chickens(P>0.05);Clostridium perfringens challenge decreased the ratio of villus height to crypt depth(V/C)by increasing the crypt depth(P<0.05);Dietary deoxynivalenol decreased the gene expression of nutrient transporter Pep T1(P<0.05).In conclusion,Clostridium perfringens challenge had the harmful effect on the development of jejunum;Dietary deoxynivalenol had the harmful effect on the nutrient transport on the jejunum of day 21 broiler chickens.Exp.2 The interactive effect of dietary deoxynivalenol and Clostridium perfringens challenge on the jejunal barrier function of broiler chickensThe results of Exp.1 indicated that dietary deoxynivalenol and Clostridium perfringens challenge had adverse effects on intestinal development and nutrient absorption function of broilers,but the effect and interactive effect on intestinal barrier function are unknown.At day 21 in the trial,the mucosa were collected to determine the genes expression of tight junction proteins(ZO-1,Occludin and Claudin-1),Muc-2,apoptotic genes(Bax,Bcl-2,Caspase-3,Caspase-8 and C-myc)and cytokine genes(IFN-?,IL-1?,TLR-4,LITAF and TLR-2)by Real-time quantitative PCR.And the content of jejunum and cecum were collected to explore the microbial community structure and evolutionary changes by 16S r DNA and the contents of SCFAs,respectively.The jejunal segment was collect to confirm the activity of DAO using assay kit.The results showed that dietary deoxynivalenol and Clostridium perfringens challenge had no effect on the genes of tight junction proteins(P>0.05).But dietary deoxynivalenol down-regulated the expression of Muc-2 and the activity of diamine oxidase was reduced by Clostridium perfringens challenge(P<0.05);Clostridium perfringens challenge up-regulated the expression of Bcl-2 and Caspase-8(P<0.05),dietary DON down-regulated the expression of Bax and Caspase-3(P<0.05).And the interactive analysis showed that they trended to antagonize the expression of Caspase-8(0.05<P<0.1).Dietary deoxynivalenol and the Clostridium perfringens challenge had the antagonistic effect on the expression of TLR-4 and LITAF(P<0.05);There were same dominant bacteria under phyla and genera level among groups.Comparing with group CP,the relative abundance of Achromobacter,Aeromonas,Asticcacaulis,Cellvibrio,Chryseobacterium,Ewingella,Flavobacterium,Helicobacter and Pseudomonas were decreased significantly in group DC(P<0.05).The interactive effect indicted that dietary deoxynivalenol and Clostridium perfringens challenge antagonized the relative abundance of Lactococcus among the top 5 genera(P<0.05).The content of SCFAs results revealed that dietary deoxynivalenol and the challenge of Clostridium perfringens had the antagonistic effect on the butyric acid(P<0.05)and the trend to antagonize the variation of acetic acid and total SCFAs(0.05<P<0.1).Spearman correlation analysis results showed that the relative abundance of Lactococcus had positive correlation with the relative expression of Caspase-3(P<0.05)and the contents of isovaleric acid and propionic acid(P<0.001),however it had negative correlation with the contents of acetic acid and total SCFAs(P<0.001).In conclusion,dietary deoxynivalenol and Clostridium perfringens challenge had harmful effect on jejunal morphology of broiler chickens;Their antagonistic effect on the relative abundance of Lactococcus so as to influence the cell death receptor pathway may be the potential mechanism of their antagonistic effect on the apoptosis response of intestinal epithelial cells.