| Toxoplasma gondii can be parasitic in humans and animals,causing zoonosis,and Toxoplasma gondii is distributed in all parts of the world.Toxoplasma gondii has a wide host,which can infect our common poultry and livestock,causing serious economic losses to animal husbandry,and it is dangerous for human life and health.Therefore,the detection and indepth study of the Toxoplasma gondii in livestock and poultry is of great significance.The main way of human infection with Toxoplasma is to eat meat products containing Toxoplasma gondii.Chicken products in meat products are one of the main meat food in our country,and the problem of chicken food safety has always been the focus of public attention,but the infection of Toxoplasma gondii in chicken products is rarely reported.Because the infection of Toxoplasma gondii in chicken products in Tai’an is not yet clear,and it has not yet been reported.This study is based on Tai’an,and then the detection of Toxoplasma infection in the heart of chicken in Tai’an city is carried out,and the preliminary study and understanding of the chicken derived Toxoplasma gondii are carried out.This study has been divided into three parts:In the first part,a new nested PCR method for detection of Toxoplasma gondii infection in chicken products was established with Toxoplasma gondii ITS-1 as a target gene,and it is proved that it has no cross reaction with other protozoa,and its sensitivity is 10~6times higher than that of traditional PCR.It is highly specific and sensitive.With using this method,compared the kit method and method of phenolchloroform to extract DNA,it is concluded that the purity of DNA extracted by the kit method is higher,and is more suitable for enzyme digestion.It was prepared for the detec-tion of Toxoplasma infection in chicken products.In the second part,360 samples of chicken heart were collected from 12 superma rkets,and 360 samples of chicken heart were collected from markets in 6 districts of Tai’an,which is Taishan District,Daiyue District,Xintai City,Feicheng City,Dongping county and Ningyang County.And the nested PCR method was applied to carry out molecular biological investigation.The results showed that 77 positive samples were detected in all samples,and the positive rate was 10.7%.The positive samples(percen tage)of Taishan,Daiyue,Xintai,Feicheng,Ningyang and Dongping were 15(12.5%),7(5.8%),21(17.5%),17(14.2),10(8.3%),7(5.8%),and the positive rate was in 5.8%to 17.5%.The difference of positive rate in different regions was significant(P<0.05).8 positive samples were detected in supermarkets and 69 positive samples were detected in the markets.The positive rate of supermarkets in Xintai was the highest,reaching 8.3%.The positive rates of supermarkets in Taishan,Daiyue and Ningyang were 0,and the positive samples were all detected in the 6 regional markets,showing that there was Toxoplasma infection in chicken heart of Tai’an chicken products,and the infection rate of supermarket products was not high.The third part,with using Mn-PCR-RFLP technology and selecting two gene loci of Toxoplasma gondii(SAG3 and GRA6),the genotyping of 77 positive samples was studied.The results showed that 77 positive samples can amplify SAG3 gene fragment and the SAG3 genotype was mainly type I and mixed infection of I/II,accounting for 93.5%.Meanwhile,an atypical genotype was found.The number 250 base"T"of the SAG3 gene fragment mutated into"C",but there is no sufficient evidence to indicate whether the effect of contingency is or is a new genotyping,and further research is needed.77 positive samples can amplify GRA6 gene fragment,and GRA6 genotype is the mainly typeⅠ,up to 98.7%.In this study,the main genotype of Tox-o plasma gondii infecting in Tai’an chicken heart products is type I. |
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