The Study Of Cross-protective Immunity Of Different Geographical Strains And Antigenic Variants Induced Precocious

In order to develop high efficient coccidium vaccine which has good immunogenicity and which are also antibiotic and provide strains and theory basis for production of chicken multivalent coccidiosis vaccine, by filtering out a strain of which immunogenicity has been different from E.maxima of Shandong,and has been preparation for the precocious strain by inducing with single oocyst separating technology, precocious inducing technology. And by pathogenicity, fecundity and determination of E.maxima of Shanxi precocious strain immunogenicity, discusses the biological characteristics of Shanxi precocious strains. The results showed that:(1) The test of single oocyst separating of E.maxima Shanxi strainCollected three different geographical strains of E.maxima, as Shanghai strains, Beijing and Shanxi strains strains, and purebred a strain of E.maxima of Shandong was got and its oocyst size was25μm-37.5μmx22.5μm-30μm and Average:30.5μm×24.32μm, shape index:1.25.(2) The test of the Cross-protective immunity of E.maxima Shandong, Shanxi, Beijing and Shanghai strainThe test of the Cross-protective immunity of the Shandong strain of E.maxima and the other different strains of E.maxima show:chickens of the strains of Shandong group has reached a good immune protection, chickens of the strains of Shanxi group relative growth rate was74.3%, the oocysts reduction rate was9.7%, ACI159.3, except RLS was28.6%, higher than the Beijing strain group was23.8%, the rest were lower than the other groups. Therefore, the results show that the Shanxi strain has the biggest difference to Shandong strain, Beijing strain by following; The test of the Cross-protective immunity of the Shanxi strain and Beijing strain of E.maxima and the other different strains of E.maxima show:Shanghai strain and Beijing strain immune Shanxi strains of group of chickens relative growth rate, oocysts reduction rate and ACI are greater than Shanghai and Shanxi strains that immune Beijing strains.The results of this two tests show:Shanxi strain has the biggest difference to Shandong strain. (3)The test of E.maxima Shanxi strain to sensitivity of coccidiostatsPOAA, RLS, ACI and ROP of Diclazuril、Toltrazuil、Oxytetracycline、Dinitolmide、Decoquinate Econazole Nitrate、Salinomycin and Sulfamonomethoxine groups were negative; Nicarbazin group of POAA and RLS were positive, ACI and ROP were negative. RLS of Madoumixing group was positive; and POAA,ACI,ROP were negative. Therefore, Drug sensitive test showed that:Eight kinds of anticoccidial drugs, including Diclazuril、Toltrazuil、Oxytetracycline、Dinitolmide、Decoquinate Econazole Nitrate、 Salinomycin、Maduramicin and Sulfamonomethoxine were sensitivity for E.maxima strain. However, Nicarbazin was mild sensitive to E.maxima precocious strain.(4) The test of precocious breeding of E.maximax precocious strainSuccessfully induced by E.maximax precocious strain which was induced by E.maxima as parent strain that was got and its oocyst size was25μm-37.5μmx22.5μm-30μm and Average:30.5μmx24.32μm, shape index:1.25.(5) The test of biological characteristics of E.maximax precocious strainBiological characteristics of the precocious strains of Shanxi E.maxima, and compares with the parental strain, the results showed that:①The latent period of E.maxima Shanxi precocious strains was109h,and it was earlier11h compared to parent strain;②The virulence of precocious strain significantly lower than the parent strain,when inoculated1.25×104-20×104cells, chickens survival rate was100%and without blood, the intestinal lesion score is less than the parental strain, weight increase following the amount of toxic attack increases, the adverse effects of the precocious and parent strains of chicken.③With increasing doses of vaccination, the relative growth rate of parental and precocious strains corresponding decline, oocyst production increased and intestinal lesion score increased.(6) In different doses of E.maxima Shanxi precocious strains to4-day-old chicks were once immune efficacy trials, in4days and11days old secondary immune efficacy test, the results showed that:When the first immunization dose greater than or equal400/only, the immune challenged group of chickens to oocysts reduction rate≥75%, reducing the rate of lesion score≥75%, relative growth rate of≥85%, intestinal lesion score≤1, ACI≥170, the mortality rate was0,reaching good immune protection. When the second immunization, a free dose and two free doses greater than or equal to100/only,200/only, the chickens immunized challenged group rate≥75%, intestinal lesion score≤1, ACI≥170, relative growth rate of≥85%, reducing the rate of lesion score≥75%, the mortality rate was0, achieving good immune protection. Therefore, the minimum immunization E.maxima Shanxi precocious strain immunization dose as400/only twice the minimum dose of immunization may be set for a free100/only, two free200/only.