تأثير الإصابة التجريبية بطفيلي الأبواغ الخبيئة على الاستجابة المناعية لأفراخ فروج اللحم الملقحة بلقاح عترة لاسوتا

الملخص EN

Two hundred forty (Ross-308) broiler chicks,Where equally randomally divided to six treatment groups;Each group composed of fourty broiler chicks.

The first group kept as control,The second group inoculated Oocyst of Cryptosporidium at seven days,The third group inoculated Oocyst of Cryptosporidium at seven days and vaccinated with live lasota strian in ten days,the fourth group inoculated Oocyst of Cryptosporidium at seven days and vaccinated with live lasota strian in fourty days,The fifth & The sixth group vaccinated with live lasot strian in ten, fourtein days respectively.

The parameters used in this study included: body weight,spleen,&bursa fabricious weight,mortalty rate,clinical signs,postmortem findings,histopathological examination and Humoral immuneresponses.The aim of this study is to know the interaction between expirmental Cryptosporidiosis with laSota strain in broiler chickens.Also the blood sample collected during the peroid (10,17,21,30,35)days to estimate the immune response by: The heamagglutenation in hibition and Enzyme-linked immunosorbent Assay (ELISA) test for the Newcastle disease of LasOta strian, The result of serological test have revealed the heamagglutenation inhibition test in the age 10 day it showed no siginificant, but differences at seventy day showed siginificant decrease in the fourth group in compare with the control group (4.25±0.479),in the (21,30,35)day it showed the increase siginificant in the fifth group(7.25±0.25,8.5±0.578,5.75±0.23).The revealed that the immune response by used indirectELISA if showed the decrease in the titer of the maternal antibody in the second group at 10 day, but showed the highest titers of antibody in the fifth group in the (17,21,30,35) days,Birds in all group showed no clinical signs,no mortality,no gross lesions,but the histo patological changes in bursa fabricious and intestine showed mor intensive in intestine 2nd,3rd ,4th groups,desequmination of intestine mucosa,cellular infiltration of inflamtory cell ,with present stages of parasite while of histo pathological lesions in bursa fabricious reveled hyperplasia,vacular degenration, presens of goblet cell in follicular&presense number of Cryptosporidium baileyi in the bursa mucosa.

Conclusion:Infection by Cryptosporidium baileyi in broiler anegative influances on body weight and immunity against ND ,WUTH histopathology chenges in bursa of fabrious and intestine.