Acta Veterinaria et Zootechnica Sinica ›› 2022, Vol. 53 ›› Issue (5): 1598-1607.doi: 10.11843/j.issn.0366-6964.2022.05.027

• BASIC VETERINARY MEDICINE • Previous Articles     Next Articles

Comparative Pathological Analysis of SPF Chicken Host Infected with Serotype 4, 8a, 8b and 11 Fowl Adenovirus Popular in China

WANG Jianlin1, JIANG Zhiyao1, LUAN Qingdong2, YIN Yanbo1*   

  1. 1. College of Veterinary Medicine, Qingdao Agricultural University, Qingdao 266109, China;
    2. Qingdao Bolong Genetic Engineering Co., Ltd., Qingdao 266041, China
  • Received:2021-09-10 Online:2022-05-23 Published:2022-05-25

Abstract: This study was conducted to investigate the pathogenicity of four serotypes of fowl adenovirus (FAdV-4, -8a, -8b and -11) that popular in China in chicken embryos and SPF chickens. Here, 12-day-old SPF chicken embryos, 10-day-old SPF chickens were infected with FAdV-4, -8a, -8b and -11 strains, respectively, the mortality of them were calculated, and body weight of embryo were measured, then gross lesions, histopathological examination and viral load in the tissues of chicken were tested. The results showed that embryo mortality was more than 45% for FAdV-8b and -11, and embryo weight loss was the greatest for FAdV-8a and smallest for FAdV-4. Chicken mortality was only present with FAdV-4 infections (53.3%) and no chicken was dead in other groups infected with FAdV-8a, -8b and -11. Besides lesions in the liver, hydropericardium, gizzard erosions, proventricular swelling and pancreatic necrosis were characteristic of chickens infected with FAdV-4, -8a, -8b and -11, respectively, and characterized by cell necrosis in parenchymal tissues accompanied by inflammatory cell infiltration. All immune organs in infected chickens possessed lesions. Compared with lesions caused by infection with FAdV-4, serious lesions were observed in chicken infected with FAdV-8a, -8b and -11. The results showed that viral loads in pancreas of chicken infected with FAdV-8b and -11 were higher than that infected with FAdV-4, and the viral loads in heart, liver and kidney of chicken infected with FAdV-4 at 5 days post infection were higher than those at 3 and 7 days post infection, and the viral load in the organs were consistent with the degree of damage in all the chickens infected, except the chicken infected with FAdV-8a. Here, we describe for the first time that the pathogenicity of these four serotypes FAdVs in embryos do not represent their pathogenicity to chickens. More attention also should be paid to FAdV-8a, -8b and -11 infections due to their severe lesions in the embryos that of the result of vertical transmission, and in the organs of the digestive and immune system that does not result in direct mortality but retard to growth and prone to secondary infection with other pathogens.

Key words: fowl adenovirus, pathogenicity, serotype, SPF chicken, embryos

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