HEMATOLOGICAL AND PATHOLOGICAL STUDY ON CHICKENS NATURALLY INFECTED BY COCCIDIOSIS IN AND AROUND AMBO TOWN, WEST SHEWA ZONE, OROMIA REGIONAL STATE, ETHIOPIA
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Date
2015-06
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Abstract
A cross sectional study was conducted from November 2014 to April 2015 with the
objective to determine hematological and pathological changes on local, Isa brown and
koekoek breeds of chickens naturally infected with coccidosis. The study involved
hematological, post mortem, mucosal scraping, gross and histopathological examinations.
A total of 113 chickens with clinical signs suggestive of coccidiosis were examined. Five
Eimeria species namely: E. tenella (48.8%), E. necatrix, (11.9%), E. brunetti (10.4%), E.
maxima (6%) and E. acervulina (3%) were identified. Reduction on the red blood cells,
Hemoglobin and decreased packed cell volume values were seen due to the effect of the
parasites. From a total of 113 chickens examined, 67 (59.3%) were positive for Eimeria
species. Fifty three (79.1%) of the coccidian positive chickens, showed visible gross
lesions in the intestine and caecum. The frequency of detection of gross lesions in
koekoek breed was significantly higher than that of local and Isa brown breeds (χ2 =
20.731, p < 0.05). Comparisons were made between microscopic & gross lesions from
small intestine and caecum and it was found that certain lesions that were graded as mild
in gross examinations showed significant microscopic lesion. Histopathological
examinations of the affected small intestine and caecum showed excessive tissue damage,
severe hemorrhagic enteritis with epithelial necrosis, presence of large clusters of
schizonts and meronts in the damaged epithelial cells along with infiltrating
inflammatory cells especially of eosinophils. In conclusion, the present study showed that
coccidiosis had a destructive effect on chickens that is represented by a high reduction in
red blood cell, packed cell volume, hemoglobin, increment in leukocyte counts and
various gross and microscopic lesions. Prevention and control methods need to be
implemented to reduce the loss due to coccidiosis.
Description
MSc Thesis
Keywords
Ambo, Chickens, Coccidosis, Eimeria, Ethiopia, Hematology, Lesion