Effect Of Catalase On Antioxidation And Intestinal Function Of Heat-stressed Broilers

With the global warming and the scale of the breeding industry,heat stress frequently occurs in broiler breeding,causing great losses to the breeding industry.Heat stress can damage the structure and function of the intestines,cause harmful bacteria or viruses to invade,damage the intestinal barrier,reduce the body’s digestion of nutrients,and also reduce the immune function of poultry and the growth performance of broilers.Heat stress is an enzyme scavenger,which has antioxidant properties,can protect intestinal function and promote the absorption of nutrients,but there are few studies on heat stress broiler anti-oxidation and intestinal function.This study established a heat-stressed broiler model to explore the effects of catalase on the anti-oxidation and intestinal function of broilers under heat-stressed environments,and provide a reference for catalase in production and breeding.In the experiment,260 1-day-old AA+ broilers were selected and fed normally for three weeks.240 were selected and randomly divided into 4 treatment groups;each with 6 replicates and each with 10 replicates.The 4 treatment groups were: control group(group C 24± 2℃),heat stress group(HS group 36±2℃),catalase group(C+CAT group 24±2℃),prevention group(HS+CAT group 36±2℃),C+CAT group Both the HS+CAT group and the HS+CAT group were supplemented with 667 mg/kg catalase in the basal diet,and the C group and the HS group were fed the basal diet.The heat stress test was started on the 21 st day of normal feeding,and the test time was 3 weeks.The effects of heat stress on 42-d broiler performance,serum biochemical indicators,antioxidant performance,intestinal tissue morphology and the relative expression of HSP70,GLUT2 and Pep T1 m RNA in the jejunum were detected.The results showed that:The effect of catalase on heat-stressed broilers on production performance: Compared with group C,The ADG,ADFI,CP,energy utilization rate and organ index of the HS group decreased significantly(p<0.01),DM was significantly decreased(p<0.05),and F/G was significantly increased(p<0.05);Compared with the HS group,the ADG of the HS+CAT group decreased significantly(p<0.01),and ADFI,DM,energy utilization rate,and organ index were significantly increased(p<0.05).The effect of catalase on blood biochemical indexes of heat-stressed broilers: Compared with group C,serum GC,GLU,BUN,AST,ALT,and Ig G in HS group were significantly increased(p<0.01),and the difference in HSP70 was significantly increased(p<0.05),The content of TP,ALB and AKP activity were significantly reduced(p<0.01),and the difference between Ig A and Ig M was significantly reduced(p<0.05);Compared with the HS group,the serum Ig A,Ig M,TP,and ALB in the HS+CAT group were significantly increased(p<0.05),and the contents of BUN,Ig G,AST and HSP70 were significantly decreased.The difference in GLU,ALT,and AKP content was extremely significant(p<0.01);Compared with group C,the differences in serum ACTH and NA in HS group were significantly increased(p<0.05),and GC was significantly increased(p<0.01);compared with HS group,the differences in serum NA and ACTH activity in HS+CAT group were significantly decreased(P<0.01),GC was significantly reduced(p<0.05);Overall,the differences in serum GLO levels in different groups were not significant(p>0.05).The effect of catalase on heat-stressed broiler anti-oxidation related indexes: Compared with group C,T-SOD,T-AOC and GSH-Px of HS group and C+CAT group were significantly reduced(p<0.01),The MDA increased significantly(p<0.05);compared with the HS group,the difference in T-SOD and GSH-Px activities in the HS+CAT group was significantly increased(p<0.05),while MDA was significantly decreased(p<0.01).The effect of catalase on the intestinal function of heat-stressed broilers: Compared with group C,the ratio of intestinal villi height and intestinal villus height/crypt depth in HS group was significantly increased(p<0.05),intestinal crypts The depth was significantly reduced(p<0.05),and the relative expression of HSP70,GLUT2,Pep T1 m RNA showed extremely significant differences(p<0.01);compared with the HS group,the histomorphology of the duodenum and jejunum in the HS+CAT group The relative expression of GLUT2 and Pep T1 m RNA is significantly different(p<0.05).Through the analysis of the above test results:Catalase can inhibit the level of HPA axis hormone secretion,reduce blood sugar content in broilers,promote protein synthesis,relieve heat stress on the structure and function of broiler intestines,and protect broiler intestinal function under heat stress.The expression of the intestinal nutrient transporter can improve the digestion and absorption of nutrients,enhance the antioxidant capacity of broilers,and ultimately effectively improve the production performance of broilers.