Study On The Mechanism Of Tannic Acid Against Infection With Eimeria Tenella

Chicken coccidiosis is a global intracellular parasitic protozoal disease.Among them,E.tenella is the most pathogenic one,in the cecum of sick chickens,diseased chickens with diarrhea,hematochezia and other symptoms,high mortality,causing huge economic losses to the poultry industry.At present,the prevention and control of coccidiosis mainly depends on chemical drugs and vaccines,but chemical drugs abuse will lead to drug residues,drug resistance and other problems,and vaccines are faced with safety,easy variation of strains,vaccine side effects and so on.Chinese herbal medicine is a natural medicine,which has the characteristics of antibacterial and anti-inflammatory,insecticidal,low drug residue,less toxic and side effects,not easy to produce drug resistance and so on.The hydrolysis products of Chinese nutgall、Phyllanthus emblica and Chestnut are tannic acid.Tannic acid has many effects,such as anti-oxidation,anti-inflammation and detumescence,relieving cough,astringent astringency and so on.In this study,by consulting a large number of literatures,ultrasonic-assisted extraction method was selected to extract tannic acid,and the model of artificial infection with E.tenella was established to explore the inhibitory effect of tannic acid on coccidia.1.Through the observation of appearance and morphology,the tannin acid of Chinese nutgall、Phyllanthus emblica and Chestnut were identified,and the tannin acid in Chinese nutgall、Phyllanthus emblica and Chestnut were extracted by ultrasonic-assisted extraction.In the range of 0.0-1.0mg/m L,a standard curve was established,and the absorbance and the concentration of tannic acid were in line with the regression equation y=0.1171x-0.001838,R~2=0.9982.y is the absorbance value of tannin acid measured at 760nm wavelength;x is the concentration of tannin acid standard solution.After calculation,the extraction rate of Chinese nutgall tannin acid is 61.24%,the extraction rate of Phyllanthus emblica tannin acid is 13.26%,and the extraction rate of Chestnut tannin acid is 25.48%.2.To determine the anti-coccidial effect of tannic acid extracted from Chinese nutgall、Phyllanthus emblica and Chestnut,the study on different concentrations of tannic acid were used to resist chicken coccidiosis.Chinese nutgall、Phyllanthus emblica and Chestnut had different concentrations of 0.005,0.01,0.02,0.04,0.06g/m L,western medicine and traditional Chinese medicine were used as control,and each chick infected with E.tenella was given 100μL/d.The relative weight gain rate,survival rate,oocyst value and disease value of chicks were recorded,and the anti-coccidiosis index(ACI)of each group was calculated.The results showed that Chinese nutgall、Phyllanthus emblica and Chestnut had the highest ACI at 0.02g/m L,which were 155.56,164.42 and 178.30 respectively.To explore the best anti-coccidial effect,Chinese nutgall,Phyllanthus emblica and Chestnut were divided into 0.18,0.20 and 0.22g/m L concentration groups,and the ACI of each group was calculated.The results showed that the anti-coccidiosis effect of Chinese nutgall was excellent when 0.02g/m L was given to each chicken,the ACI was180.0,the ACI of Phyllanthus emblica was 160.1,and the ACI of Chestnut was 175.73.E.tenella oocystis spores were inhibited by0.02g/m L Chinese nutgall,Phyllanthus emblica and Chestnut at 12-72h.3.To explore the effect of tannic acid on the growth of E.tenella,the DNA content of coccidia was detected by Real time Quantitative PCR(q PCR),and the best concentration of tannic acid to inhibit the development of E.tenella was calculated.12-72 hours after worm attack,the relative survival rate of MDBK cells was higher than90%when tannic acid extracted by the three drugs was 0.1μg/m L.Sporozoites are parasitic on MDBK cells and gradually develop into trophozoites,first-generation merozoites and second-generation merozoites in host cells.After release from host cells,the second-generation merozoites die gradually,but the nutrition of MDBK cell medium is limited.At 72h,a large number of cells die.So the content of DNA was measured at 24h,48h and 72h.The results showed that tannic acid extracted from three kinds of Chinese herbal medicine had good inhibitory effect on sporozoite development,and there was no significant difference among the three kinds of tannic acid at the same dose.The drug concentration of 0.1μg/m L not only had low toxicity to MDBK cells,but also had good inhibitory effect on coccidia proliferation.