Effect Of Catalase And Meloxicam On DSS-induced Yellow-feather Chickens Intestinal Injuries And Dysbacteriosis

Production performance in poultry industry is closely related to gut health.Gut health is determined by gut barrier integrity and gut microbiota.During the production process,some pathogenic microorganisms or toxin can impair gut barrier integrity,disturb intestinal flora,trigger gut inflammation and oxidative stress,endanger animal health and cause significant economic loss.In previous studies,we established a model of intestinal barrier damage and inflammation of broilers induced by dextran sulfate sodium(DSS).This study,by adding antioxidant catalase(CAT)and anti-inflammatory drug meloxicam(MEL)to feed,respectively,explore the effects of antioxidant and anti-inflammatory effects on DSSinduced intestinal injuries and dysbacteriosis.270 broilers at the age of 1 day were randomly divided into six groups,with 3replicates in each group(n = 15 per replicate).The blank control group and DSS negative control group were fed basic diets,the CAT control group and DSS+CAT group were fed with 100 mg/kg CAT basic diets,the MEL control group and DSS+MEL group were fed with 5 mg/kg MEL basic diets.On day 12,the DSS negative control group,DSS+CAT group and DSS+MEL group of broilers received 1.25% DSS supplemented in the drinking water for 14 days(challenge phase),followed by normal water for 7 days(recovery phase).The blank control group,CAT control group and MEL control group drank water normally throughout the experiment.On day 26 and 33,the broilers were sacrificed and sampled.The main results are as follows:1.Phenotypic results: compared with the negative control group of DSS,the weight gain of DSS+CAT group broilers was significantly increased during the recovery phase(P< 0.05),but had no significant difference in mortality,fecal score,intestinal pathology score and immune organ index(P > 0.05).While the spleen index and bursa of Fabricius index of DSS+MEL group broilers was significantly increased during the challenge phase(P <0.05),and the spleen index was no significant difference(P > 0.05),the bursa of Fabricius index was significantly increased during the recovery phase(P < 0.05),but had no significant difference in mortality,fecal score,intestinal pathology score,and stage weight gain(P > 0.05).2.Jejunal intestinal morphology and tight junction protein expression: compared with the negative control group of DSS,the crypt depth of DSS+CAT group broilers was significantly reduced(P < 0.05),the jejunal V:C ratio,the jejunal ZO-1 and Claudin-1m RNA expression was significantly increased(P < 0.05);but there was no significant difference in the jejunal V:C ratio and the tight junction protein expression in the DSS+MEL group broilers(P > 0.05).3.Serum and liver antioxidant indexes: compared with the negative control group of DSS,during the challenge phase the MDA content in liver of DSS+CAT group broilers was significantly decreased(P < 0.05),total antioxidant capacity(T-AOC)was significantly increased(P < 0.05),serum antioxidant index was no significant difference(P > 0.05).And during the recovery phase the MDA content in liver was significantly decreased(P < 0.05),T-AOC was no significant difference(P > 0.05),serum antioxidant index was no significant difference(P > 0.05).While DSS+MEL group broilers had no significant difference in serum and liver antioxidant indexes during the challenge and recovery phase(P > 0.05).4.Serum inflammatory factors: compared with the negative control group of DSS,Serum TNF-α and IL-6 levels of DSS+CAT group and DSS+MEL broilers was no significant difference during the challenge and recovery phase(P > 0.05).5.Cecal microbes: compared with the negative control group of DSS,during the challenge phase the cecal microbial diversity and richness of DSS+CAT group broilers was increased significantly(P < 0.05).While during the recovery phase cecal microbial diversity was not significant difference(P > 0.05),cecal microbial richness was increased significantly during the recovery phase(P < 0.05).Compared with the negative control group of DSS,during the challenge phase the cecal microbial diversity of DSS+MEL group broilers was increased significantly(P <0.05),cecal microbial richness was not significant difference(P > 0.05).While during the recovery phase cecal microbial diversity was not significant difference(P > 0.05),cecal microbial richness was increased significantly(P < 0.05).In summary,the main conclusions of this study are:1.Feeding with 100 mg/kg CAT basic diets significantly improve the antioxidant capacity of broilers,increased the m RNA expression of tight junction protein in the jejunum,protect the intestinal integrity,and thus alleviate the decline in broilers growth performance and dysbacteriosis caused by DSS.2.Feeding with 5 mg/kg MEL basic diets significantly promote immune organs development in the jejunum,alleviate the broilers dysbacteriosis caused by DSS,but it has no significant effect on the decline in growth performance of broilers.