OCCURRENCE AND IDENTIFICATION OF EIMERIA SPECIES IN CHICKEN, TURKEY AND QUAIL
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Date
2021-07-30
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR
Abstract
The study was undertaken during the period from June 2019 to December
2020 with the objectives of studying the occurrence of Eimeria spp. in chicken,
turkey and quail in organised poultry farms and backyard poultry units by
conventional methods and molecular confirmation of Eimeria spp. in chicken by
polymerase chain reaction (PCR). A total of 300 chicken, 150 quail and 50 turkey
faecal samples collected from organised poultry farms and backyard poultry units
in and around Thrissur district were examined by conventional methods for
morphological identification of Eimeria species. Twenty-six intestinal samples of
coccidiosis suspected chicken and two samples from quail were also collected
from post mortem cases from the department of Veterinary Pathology, College of
Veterinary and Animal Sciences, Mannuthy. The overall occurrence of Eimeria
spp. was 37.66 per cent (113/300) in chicken and 16.66 per cent (25/150) in
quails. None of the samples collected from turkeys were found to be positive for
Eimeria spp. The species of Eimeria identified on morphological examination
were E. tenella, E. necatrix and E. maxima in chicken and E. bateri and E.
tsunodai in quail. The occurrence rate of E. tenella was found to be significantly
higher (46.01 %) compared to E. necatrix (39.82 %) and E. maxima (14.15 %).
The rate of occurrence of Eimeria infection was found to be significantly higher
in backyard poultry (45.86 %) and during the monsoon season (43.13 %). Gross
lesions found in the intestine and caeca of chicken included ballooning of intestine
with petechial haemorrhages, distended caeca filled with blood and thickened
caecal and intestinal walls, with average lesion score of 3+ and 2+, respectively.
In quail the gross lesions included ballooning of the intestine and caeca with
blood in the contents and the average lesion score was 2+. The histopathological
examination of intestinal and caecal lesions in chicken revealed marked
destruction of villi with schizonts and the immature oocysts in the epithelial cells.
In quail the histopathological examination of intestine and caeca revealed
desquamation of epithelium, destruction of villi and presence of various
developmental stages of Eimeria. The genomic DNA was isolated from the
sporulated oocysts of Eimeria spp. and tissue samples. The PCR protocol was
standardised by gradient PCR using primers targeting the ITS-1 region of the
seven Eimeria spp. in chicken. Out of 63 samples confirmed by conventional
methods, 60 samples yielded PCR results of which, 29 (48.33 %) were positive
for E. tenella, 23 (38.33 %) for E. necatrix and eight (13.33 %) for E. maxima.
The amplicons of E. tenella, E. necatrix and E. maxima were sequenced and
submitted to Gen Bank and the phylogenetic analysis was carried out. Partial ITS 1 region of Eimeria spp. in quail was amplified using universal primers,
sequenced and submitted to Gen Bank. This study forms the first report of
molecular identification of Eimeria spp. in chicken in Kerala. To the best of our
knowledge, this also forms the first report of identification of Eimeria spp. in
quail in Kerala.
Description
Thesis Submitted in the partial fulfillment of the requirement for the degree of Master of Veterinary Science in Veterinary Parasitology