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OJVRTM
Online
Journal of Veterinary Research©
Volume
22 (2): 139-149, 2018.
Effects of relative humidity and commercial
medicinal treatments
on complex respiratory infections and
pathology in broilers.
Faghihzadeh S., DVM, Asasi K., DVM, PhD, Abdi-Hachesoo
B., DVM, PhD.
Poultry
Diseases Research Center, Department of Clinical Studies, School of Veterinary
Medicine, Shiraz University, Shiraz, Iran.
ABSTRACT
Faghihzadeh S, Asasi
K, PhD, Abdi-Hachesoo B., Effects of relative
humidity and commercial medicinal treatments on complex respiratory infections
and pathology in broilers. Onl J Vet Res., 22 (2): 139-149, 2018. Respiratory complex infections are the most common cause of mortality
in broiler chicken farms in developing countries. We report effects of 25 to
80% relative humidity (RH) on treatments with Bromhexine®
and Bronchimax® in broilers inoculated
with infectious bronchitis virus (IRFIBV32), avian influenza virus (H9N2) and E.
coli (O2). Nine groups of 43 broiler chicks were challenged and 3
groups of 20 were used as unchallenged controls but all received treatments and
were exposed to 3 levels of RH. Results showed highest mortality rates (28%)
occurred at low relative humidity in broilers given Bronchimax®
and lowest mortality (11.5%) in high relative humidity without treatments (P
< 0.05). Oral mucosal discharges were significantly higher in
groups exposed to high humidity with Bromhexine
and/or high humidity with Bronchimax compared with
other groups (P≤0.05). Syrinx casts, were lower in those exposed to
50-55% RH and treated with Bromhexine (P≤0.05).
In dead
birds, aggregation of fibrinous exudate occluded the syrinx leading to asphyxiation. We report clinical signs, necropsy findings, tracheal histopathology,
ciliary stasis scores, serology and RT-PCR
results for all poultry affected by complex respiratory disease. High
relative humidity may decrease mortality but mucolytic and/or herbal
treatments, increase mortality in chickens infected with respiratory complex
agents.
Key Words:
Respiratory Complex, Relative Humidity, Mucolytic drugs, IBV, H9N2, E. coli.