Effects Of Fumaric Acid On Growth Performance,Hematology Index And Small Intestinal Function Of Broilers Under Constant Heat Stress

The effects of fumaric acid on growth performance,hematology index and intestinal function of broilers under sustained heat stress were studied in this experiment to alleviate the effects of sustained heat stress on production performance,slaughter performance,routine blood test,biochemical indicators intestinal microorganisms and expression of nutrient transporters in intestinal mucosa.180 Rose 308 broilers were randomly divided into five groups:control group(CONT),heat stress control group(HS),diet+0.5%fumaric acid(HS+0.5%FA),diet+1.0%fumaric acid(HS+1.0%FA),diet+1.5%fumaric acid(1.0%FA),and diet+1.5%fumaric acid(1.0%FA).Thermal stress group of fumaric acid(HS+1.5%FA).Each treatment group was replicated in 4 groups,with 9 chickens per replicate.The feed intake,water intake,number of deaths and weight gain of broilers in each group were recorded every day after the start of the experiment.At 28,35 and 42 days,2 broilers were randomly selected and 8 broilers were weighed for half-clean weight,full-clean weight and pre-slaughter live weight.Slaughter rate,half-clean rate,full-clean rate,muscle dehydration rate and dry matter rate were calculated and shear force was measured on slaughter day.Blood routine(RBC,WBC,PLT and HGB)was measured by EDTA-Na2 and biochemical parameters(Glu,TP and TG)were measured by 5 ml without anticoagulant.Duodenum,jejunum and ileum were taken and put into aseptic bags for colony counting of small intestinal contents.The duodenum,jejunum and ileum mucosa were washed with ice saline,scraped under sterile condition and stored in EP tube treated with DEPC.The expression of SGLT1,PepT1 and FATP1 in small intestinal mucosa was measured.The test results show that:1.Effects of fumaric acid on growth performance,slaughter performance and meat quality of broilers under constant heat stressCompared with HS group,the mortality of broilers in heat stress group with 1.0%and 1.5%FA decreased significantly(P<0.05);compared with CONT group,the daily gain of broilers decreased at 28,35 and 42 days,and the daily gain of broilers with fumaric acid increased;the feed weight ratio of broilers in HS group was significantly higher than that in CONT group at 35 days(P<0.05),and the dietary fumaric acid decreased the feed weight ratio in HS group.The amount of the drug in CONT group was significantly higher than that in CONT group(P<0.01 or P<0.05).Compared with the CONT group,the slaughter rate,semi-clean chamber weight and total net chamber weight of broilers in HS group decreased significantly(P<0.01 or P<0.05),while the semi-clean chamber rate and total clean chamber rate increased significantly(P<0.01 or P<0.05).The slaughter rate of broilers in HS+0.5%FA group increased significantly(P<0.05),and the semi-clean chamber rate and total clean chamber rate of broilers in HS+1.5%FA group decreased significantly(P<0.05 or P<0.05).Compared with CONT group,the rate of muscle dehydration in heat stress control group increased significantly.At 42 days,the rate of leg muscle dehydration in HS group increased significantly(P<0.01),the rate of leg muscle dry matter in HS+1.5%FA group decreased significantly(P<0.01),the rate of leg muscle dry matter in HS group decreased significantly(P<0.01 or P<0.05)compared with CONT group at 28 days and 35 days,and the rate of breast muscle dry matter in HS group decreased significantly(P<0.05).2.Effect of fumaric acid onhematological index of broilers under constant heat stressCompared with CONT group,the levels of WBC and HGB in blood of broilers in HS group decreased significantly at 28 days(P<0.05).On 35 days,the levels of RBC,PLT and HGB in blood of broilers in HS group decreased significantly(P<0.01 or P<0.05),WBC content increased significantly(P<0.01),and HGB content in broilers in HS group decreased significantly at 42 days(P<0.05).Compared with HS group,the WBC content in HS+0.5%FA group increased significantly(P<0.05),HGB content in HS+1.5%FA group increased significantly(P<0.05),WBC content in broilers decreased significantly(P<0.01 or P<0.05),HS+0.5%and 1.0%FA group increased significantly(P<0.01 or P<0.05).Compared with the CONT group,the serum Glu content in HS group increased significantly(P<0.01)and the serum TP content in broilers decreased significantly(P<0.05)after 42 days.Compared with HS group,the serum Glu content of broilers in HS+1.5%FA group decreased significantly at 28 days(P<0.01),and the serum Glu content of broilers in HS+0.5%and 1.5%FA group decreased significantly at 42 days(P<0.01),while the serum TP content of broilers in HS+0.5%FA group increased significantly(P<0.05).3.Effects of fumaric acid on intestinal microorganisms in broilers under constant heat stressCompared with CONT group,the total bacterial count and Lactobacillus content in duodenum and jejunum of broilers in HS group decreased significantly at 28 days(P<0.01 or P<0.05),Clostridium perfringens production in duodenum increased significantly(P<0.01),total bacterial count and Clostridium perfringens production in duodenum of broilers increased significantly at 35 days(P<0.01),and Lactobacillus content in jejunum decreased significantly(P<0.01).The total bacterial count of duodenum decreased significantly(P<0.01),Clostridium perfringens in duodenum,jejunum and ileum increased significantly(P<0.01),and lactic acid bacteria in duodenum and jejunum decreased significantly(P<0.01).Compared with HS group,the content of Clostridium perfringens in duodenum and jejunum in HS+1.0%FA group decreased significantly(P<0.01)and Lactobacillus in jejunum and ileum increased significantly(P<0.01);Clostridium perfringens in duodenum and Lactobacillus in broiler chickens decreased significantly(P<0.01 or P<0.05)and Clostridium perfringens in duodenum and ileum in HS+1.0%FA group increased significantly(P<0.01 or P<0.05),and Clostridium perfringens in jejunum and ileum in HS FA The bacteria decreased significantly(P<0.01 or P<0.05).4.Effect of fumaric acid on expression of nutrient transporter in intestinal mucosa of broilers under constant heat stressCompared with CONT group,the expression of PepTl in duodenum and FATP1 in jejunum of broilers in HS group decreased significantly at 28 days(P<0.05),and SGLT1 expression in duodenum and jejunum of broilers increased significantly at 35 days(P<0.01 or P<0.05),while the expression of PepTl and FATP1 in duodenum decreased significantly(P<0.05);at 42 days,the expression of SGLT1 in duodenum and ileum of broilers decreased significantly(P<0.05).The expression of PepT1 and FATP1 in duodenal mucosa decreased significantly(P<0.01 or P<0.05),while the expression of PepTl in jejunum decreased significantly(P<0.05).Compared with HS group,the expression of PepT in ileum was significantly increased in HS+1.0%FA group at 28 days(P<0.05),the expression of FATP1 in jejunum was significantly increased in HS+0.5%FA group(P<0.05),the expression of SGLT1 in duodenum and jejunum was significantly decreased in broilers at 35 days(P<0.05),and the expression of PepTl and FATP1 in duodenal mucosa was significantly increased in HS+0.5%FA group(P<0.05),and in broilers at 42 days,HS+0.0%FA group.In 5%FA group,the expression of SGLT1 in duodenum decreased significantly,while the expression of PepTl and FATP1 increased(P<0.01 or P<0.05).Conclusion:Constant heat stress significantly increased mortality,water consumption,half-empty rate,full-empty rate,muscle dehydration rate and blood leucocyte content of broilers,decreased daily gain,slaughter rate,half-empty and full-empty weight,muscle dry matter content and blood erythrocyte,platelet and hemoglobin content of broilers.In addition,constant heat stress caused intestinal harmful bacteria(producing capsule).Clostridium increased,beneficial bacteria(lactobacillus)decreased,and changed the expression of nutrient transporter mRNA in small intestinal mucosa.The expression of SGLT1 increased,while the expression of PepTl and FATP1 decreased significantly.Adding 0.5%fumaric acid in heat stress group could increase slaughter rate,half-and full-bore weight,reduce muscle dehydration rate,increase muscle dry matter content,decrease WBC content in blood and increase RBC,HGB and PLT content of broilers.Adding 1.0%fumaric acid in diet could reduce mortality,increase daily gain,reduce feed-Weight ratio,and decrease SGLT 1 expression,increase PepTl and FATP 1.Dietary addition of 1.5%fumaric acid canreduce the total number of intestinal bacteria and clostridium perfringens,and increase the number of lactic acid bacteria.The addition of fumaric acid reduces the mortality rate of broilers,improves the production and slaughter performance of broilers,improves the muscle quality of broilers,improves the transport efficiency of oxygen and nutrients in blood,alleviates the changes of hematological indicators caused by heat stress,plays a certain role in resisting heat stress,maintains the microecological balance of intestinal tract,and maintains the normal function of intestinal tract.It can alleviate the damage of intestinal tract caused by heat stress and make intestinal tract play a better digestive and absorption function,which is conducive to the growth and development of broilers.Therefore,fumaric acid can be used as feed additive to alleviate the effects of persistent heat stress on broiler performance,hematology and intestinal function.