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The Thai Journal of Veterinary Medicine

Abstract

This study was designed to investigate the pathogenesis of infectious bronchitis virus (IBV), a new variantgenotype and QX-like IBV, isolated in Thailand. Sixty, 28-day-old, female broiler chickens were divided into 3 groupsof 20 chickens each (groups 1-3) and sixty, 1-day-old, female broiler chickens were divided into 3 groups of 20chickens each (groups 4-6). The chickens in groups 2 and 5 were inoculated with QX-like IBV (isolate THA80151)whereas the chickens in groups 3 and 6 were inoculated with a new variant genotype IBV (isolate THA90151). Thechickens in groups 1 and 4 served as negative control groups. Clinical signs and mortality rates were observed for 14days post-inoculation (dpi). The chickens were weighed at 0, 7 and 14 dpi. At 7 and 14 dpi, five chickens per groupwere humanely killed. The tracheas and kidneys were collected for IBV detection and histopathological lesion scoreevaluation. The results revealed that at 7 dpi, the average body weight of the chickens in groups 2 and 6 wassignificantly lower than that of the negative control groups (groups 1 and 4, respectively) (p<0.05). Groups 2 and 5had one dead chicken in each (5% per group). As for the histopathological lesion score evaluation, lesion scores forthe trachea were not significantly different among infected groups (p>0.05) at 7 dpi but the score for group 5 wassignificantly higher than that for group 2 at 14 dpi (p<0.05). As for the kidneys, there was no significant difference inthe lesion score among the infected groups at both 7 and 14 dpi (p>0.05). This study indicates that both of the ThaiIBV isolates have an affinity to cause respiratory and kidney lesions and an effect on growth rate was found over 7dpi.

DOI

10.56808/2985-1130.2366

First Page

51

Last Page

57

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