Differential susceptibility and immune response in chicken and Japanese quail towards Avibacterium paragallinarum

Abstract

ABSTRACT This study was designed to assess variation in the development of clinical signs, the associated pathological changes and immune activation following experimental Avibacterium paragallinarum (Av. paragallinarum) infection in chicken and Japanese quail. Thirty-three, 4-week-old chicken and Japanese quail were divided into 3 groups, namely (1) naïve control (unhandled) containing 3 birds in each, (2) ‘sham-inoculated (sterile PBS inoculated) group’ with 9 birds in each and (3) ‘infected group (Av. pargallinarum infected) with 19 birds in each. Birds were inoculated with 1.8 × 108 CFU/mL of Av. paragallinarum, while sham inoculated received sterile PBS without Av. paragallinarum. Daily clinical monitoring; blood and tissue samples were collected on 0, 3, 5 and 12 days post-infection. Haemagglutination inhibition (HI) and serum oxidative index were measured to assess immune activation. Nasal discharges constituted prominent clinical signs in chicken. Japanese quail elaborated quicker, slightly higher seroconversion in the HI test. The observed immunoprotection mediated via oxidative changes (systemic malondialdehyde (MDA) level) indicated an unusual way of protection provided by inflammatory leukocytes. Trans-epithelial migration of KUL01+ cells following the putative release of chemo-attractants by turbinates epithelium was evident. Action by reduced glutathione levels (neutralizing MDA) in chicken, not in Japanese quail, suggests species-specific differences of innate immunity against infection.