Effects Of Fulvic Acid On Broiler Performance,Blood Biochemistry And Intestinal Microflora

In recent years,the environmental pollution and bacterial resistance problems caused by the use of antibiotics have become increasingly prominent,and the search for antibiotic alternatives has been a hot topic of discussion among researchers in the livestock industry.Fulvic acid,as an important component of humic acid substances,can improve the production performance of broiler chickens and is expected to become a new alternative antibiotic feed additive.The purpose of this study was to investigate the effects fulvic acid on broiler production performance,slaughter performance,blood biochemistry,antioxidant function,immune performance and intestinal microflora,to evaluate the role of fulvic acid in broiler production and provide a basis for future practical application.In the experiment,360 AA broilers with similar body condition and good health were randomly divided into 5 groups with 6 replicates each and 12 chickens in each replicate.The control group(C)was fed with the basal diet,and the treated groups(I,II,III and IV)were supplemented with 0.05%,0.1%,0.2% and 0.3% of mineral fulvic acid respectively on the basis of the control group.The total experimental period was 35 days,divided into the first(1-21 days)and the second(22-35 days).Body weight and residual material weight were weighed at the beginning and end of each stage by replicate,and two chickens were randomly selected from each replicate at the end of the experiment,and after blood collection from the wing vein.Heart,liver,spleen,thymus,bursa franca,jejunum,cecum,and cecum contents were collected after slaughter.The results showed that:(1)Production performance results showed that compared with the control group,fulvic acid improved the average body weight and average daily weight gain of broilers from 1 to 21 days old(P<0.05),among which the treated group II was higher than the other groups.The addition of fulvic acid at the second stage(22～35 days of age)significantly increased the average body weight(P<0.05),increased the average daily weight gain and average daily feed intake,and reduced the FCR of chickens in each treated group,with no significant difference between the treated groups(P>0.05).From the whole period,fulvic acid could significantly increase the average body weight and daily weight gain of broilers(P<0.05).The addition of fulvic acid had no effect on the slaughter performance of broilers(P>0.05),but the pectoral muscle rate of treated group II was extremely significantly higher than that of the control group(P<0.01),and the leg muscle rate of treated group I and III was significantly lower than that of the control group(P<0.05).Fulvic acid had decreased the p H of leg muscle very significantly compared with the control group(P<0.01);fulvic acid had no effect on organ weight in each treated group(P<0.05),but increased thymus weight(P<0.05).(2)The results of blood biochemical,antioxidant and immune indexes showed that compared with the control group,the AST activity of treated group III was significantly higher at 35 days of age(P<0.05),the serum GSH-Px activity of treated group IV was significantly lower at 21 days of age(P<0.05);at 35 days of age,the difference of the total serum antioxidant capacity between treated group II and control group was significant(P<0.05),CAT activity in treated group III was highly significant(P<0.01),SOD activity in treated group II was significantly higher than the control group(P<0.05),and MDA content gradually decreased and the difference was significant(P<0.05).The addition of different concentrations of fulvic acid significantly increased the Ig A and Ig G contents in the serum of broiler chickens at 21 and 35 days of age(P<0.05).(3)The results of 16 S r RNA sequencing of broiler cecal microorganisms at 21 and 35 days of age indicated that fulvic acid increased the abundance of Barnesiella,Lachnospiraceae,Alistipes,Lactobacillus,Christensenellaceae at 21 and 35 days of age.Alpha diversity results pointed out that the cecum microorganisms differed significantly at the genus level at 21 days of age(P<0.05)between the treated I and IV groups and the control group(C).At 35 days of age,significant differences were observed between the treated group III and the control group(C)(P<0.01),and PCo A analysis results showed that composition of microflora in the treated III group at 21 and 35 days of age was different with that in control group.COG and KEGG functional annotation showed that the cecum microbial gene functions in each treated group were mainly enriched in carbohydrate metabolism,amino acid metabolism and energy metabolism at each stage.The addition of fulvic acid did not significantly improve those pathways.In conclusion,fulvic acid could improve the production performance of broiler chic kens,had an effect on blood biochemical and antioxidant properties,increased the immu noglobulin content,enhanced the immunity function,and increased the abundance of Ba rnesiella,Lachnospiraceae,Alistipes,Lactobacillus,Christensenellaceae and other benefic ial bacteria in each stage of the cecum.The optimal level of fulvic acid addition was0.1%.