Therapeutic effect of Artemisia argyi essential oil nasal drops on avian infectious bronchitis

Abstract

ABSTRACT This study aimed to explore the therapeutic activity of Artemisia argyi essential oil (AAEO) nasal drops against avian infectious bronchitis and the underlying mechanism in the avian respiratory tract. Overall, 96 14-day-old broilers were randomly divided into 4 groups: control (control), A. argyi essential oil (AAEO) control, infectious bronchitis virus (IBV), and AAEO treatment (IBV + AAEO) groups (n = 24/group). Mortality was 25% (6/24) in the IBV group compared to 4.2% (1/24) in the AAEO treatment group. The clinical symptoms of the treatment group were significantly improved compared with those of the IBV group after 5 days of treatment. The broilers recovered at the end of the experiment. AAEO treatment relieves IBV-induced tracheal mucosal edema and bleeding and inhibits viral replication in the lungs. In addition, it enhanced SIgA secretion in the tracheal mucosa and increased type I interferon release by regulating IRF7 expression. Furthermore, we explored the mechanism underlying the therapeutic effect of AAEO. It maintains TLR7 at a high level in broilers and further upregulates MyD88, IRF7, and IL–10. Thereby enhancing the immune system and anti-inflammation. Our results suggest that AAEO can be used as a therapeutic agent for IBV.