| A certain level of oil added into the diet can replace carbohydrates and proteins of equal energy,appropriately extend the residence time of chyme in the digestive tract,and contribute to better digestion and absorption of nutrients in the diet.However,the oxidation of unsaturated fatty acids or other lipids in oils and fats during transportation,processing and storage will lead to oxidative rancidity and odor,which will reduce the nutritional characteristics of diets,seriously affect the body’s antioxidant system and lead to oxidative stress.Pueraria belongs to the leguminous plant,grows in most areas of our country,and the root is mainly used as medicine,having the function of relieving muscle and antipyretic,producing saliva and quenching thirst,rising the sun and stopping diarrhea,etc..Puerarin is the extract of pueraria root,can clear the body’s excess free radicals,improve the body’s antioxidant capacity,reduce the body’s oxidative damage,in the immune aspect also has a significant impact.Therefore,the purpose of this study was to investigate the effect of dietary addition of oxidized soybean oil and puerarin on antioxidant capacity,immune function and intestinal microflora of broilers.A total of 360 healthy 1-day-old Sanhuang broiler chickens were randomly divided into 4 treatment groups with 6 replicates in each group and 15 chickens in each replicate.The four treatment groups were fed a diet of fresh soybean oil,fresh soybean oil + puerarin(750mg/kg),oxidized soybean oil and oxidized soybean oil + puerarin(750mg/kg),respectively.At the ages of 28 days and 56 days,one chicken was randomly selected for each repeat in each group.Blood samples were collected from chicken wing veins for the determination of serum related biochemical indicators.Ileum and cecum mucosa were used to determine the indexes of caecum oxidation and immunity in broilers.The caecum contents were collected in a sterile environment,and the structure and diversity of caecum flora were determined based on Miseq detection technology.The results showed as follows:1.The oxidized soybean oil in the diet significantly reduced the serum Trx R content and the relative expression of Trx R1 m RNA in the caecum of 28-day-old broilers,and the relative expression of Nrf2 m RNA showed a decreasing trend(P<0.1),leading to oxidative stress.Dietary addition of puerarin significantly inhibited carbonylated proteins in broilers aged 28 and 56 days(P<0.05),and significantly increase the relative expression levels of Nrf2,HO-1 and gsh-px m RNA in broilers aged 28 days(P<0.05),while the relative expression levels of Nrf2,Trx RI,HO-1 and gsh-px m RNA in broilers aged 56 days(P<0.05).Therefore,the addition of puerarin has a regulatory effect on the occurrence of oxidative stress.2.Diets containing oxidized soybean oil significantly reduced intestinal s Ig A secretion in 28-day-old broilers(P<0.05).Dietary addition of puerarin significantly increased serum Ig A content and intestinal s Ig A secretion in 28-day-old broilers(P<0.05),and serum Ig A and Ig G content in 56-day-old broilers(P<0.05).(2)at the age of 28 days,the relative expression of oxidized soybean oil on TLR21 m RNA in broilers’ cecum showed a decreasing trend(P<0.1),and the relative expression of zo-1 and COLEC10 m RNA in broilers’ cecum significantly decreased(P<0.05),which significantly increased the relative expression of Av BD2,Av BD8,Av BD9 and Av BD11 m RNA in broilers’ cecum(P<0.05).At the age of 56 days,the relative expressions of zo-1,Av BD5,Av BD10 and Av BD14 m RNA in the caecum of broilers were significantly decreased(P<0.05).Fodder,puerarin is added to the age of 28,chicken caecum Claudin 1 and COLEC12 m RNA expression of relative volume increased significantly(P < 0.05),living,Av BD2,Av BD14 m RNA expression of relative quantity decreased significantly(P < 0.05),Av BD8 there is a decrease in the amount of m RNA expression(P < 0.1),the trend of puerarin to 56 days of age chicken caecum Occludin,Claudin 1 and COLEC10 m RNA expression of relative quantity increased significantly(P < 0.05),The relative expression levels of TLR2,TLR4 and NLRC5 m RNA in cecum were significantly decreased.3.According to the analysis of sobs index,chao index,ace index,shannon index and Simpson index,sobs index,chao index and ace index were significantly increased at the age of 28 days under the condition of feeding and oxidizing soybean oil.Compared with the fresh soybean oil,the samples of oxidized soybean oil were more similar to each other.The similarity of different samples was higher when puerarin was fed than when not fed.The composition similarity of the samples of oxidized soybean oil at 56 days old was higher than that of fresh soybean oil.The similarity between puerarin and unfed samples was close.The oxidized soybean oil in the diet has a certain effect on the intestinal flora structure and diversity of broilers,and the addition of puerarin in the diet can improve the intestinal flora structure and enhance the ability of the body to resist stress.The specific mechanism still needs to be further studied.In summary,the oxidized soybean oil can reduce the antioxidant capacity of the cecum of broilers by activating the Nrf2 signaling pathway,and damage the intestinal barrier function of poultry,while the addition of pueraria in diet can partially reverse the negative effects caused by oxidized soybean oil. |
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