الفهرس 
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Abstract
Twenty-eight broiler chicken farms from 16 to 70 days of age were examined clinically for suspected outbreaks of coccidiosis in eight governorates in Egypt. Flock history, clinical signs, dropping score and lesion score were recorded at time of examination. Fecal as well as intestinal samples (from different intestinal portions) were examined for coccidiosis using direct wet smear. Positive samples subjected to DNA extraction followed by amplification of internal transcribed spacer 1(ITS1) region of Eimeria genome with species specific primers of E. tenella, E. necatrix, E. maxima and E. acervulina for detection of these species using conventional PCR. The ITS1 region of ribosomal DNA (rDNA) from highly positive sample of single infection with E. tenella was sequenced and compared with sequence of ITS1 region of E. tenella strain in coccivac-B Vaccine. Results revealed that, the highest mortality rate (2.49%) was recorded in cobb breed in Dakahlia governorate while the lowest mortality (0.5%) was recorded in avian species in Dakahlia and Damitta governorate. Mean lesion score revealed that higher score in different types of chickens attributed to cecal portion 0.6-3.3 and lower score was observed in other portions 0-0.4 in duodenal portion, 0-0.9 in jejunal portion and 0-0.6 in illiual portion. PCR results revealed the prevalence of E. tenella 100% then E. necatrix 28.57 % from positive cecal and fecal samples, E. acervulina 21.42% from positive intestinal and fecal samples. Our sequence revealed 98% identity with coccivac -B E.tenella ITS-1 sequence. The locally isolated and molecularly identified E. tenella field isolate was subjected for propagation and pathogenicity testing. Experimentally anti-coccidial vaccine (Coccivac-B), probiotic (Bactocell) and nanoparticles (zinc oxide nanoparticles) were compared as preventative and control measures against coccidiosis in broilers reared in floor pen. Criteria for evaluation were clinical signs, droppings score, mortality, mean lesions score, oocyst counts, histopathology, immunological parameters ( organ body weight ratio, lysosomal activity testing and nitric oxide activity testing )and performance (mean body weight, mean weight gain, feed intake and feed conversion ratio). Both vaccinated / Bactocell and vaccinated groups decreased clinical signs, dropping score and oocysts count in comparison with Bactocell and zinc oxide nanoparticle group. Zinc oxide nanoparticle group greatly reduced histological changes then Bactocell group followed by vaccinated/Bactocell group and vaccinated group respectively. No mortality was recorded in all treated groups. The weight of bursa of Fabricius was affected in all groups at the 7th day P.I. in comparison with blank group but weight of thymus and spleen not affected. Mean of nitric oxide activity test was low at blank group, vaccinated group and zinc oxide nanoparticle group respectively at all times of examination. Mean of lysosomal activity test revealed that blank group was of the highest value allover different times of examination while the lowest value was at control infected group. Mean body weight slightly affected in vaccinated group, zinc oxide nanoparticle group, vaccinated/Bactocell group and Bactocell group respectively. Total FCR slightly affected in vaccinated/Bactocell group, vaccinated group and zinc oxide nanoparticle group in comparison to blank group but Bactocell group was of the highest value. According to results of sequencing, high identity percentage of E. tenella isolate sequence with sequence of E. tenella in Coccivac-B revealed high protection level against experimental coccidiosis.