Mitigating impact of Glycyrrhiza glabra on virulent Newcastle disease virus challenge in chickens: clinical studies, histopathological alterations and molecular docking.

Background: Newcastle disease (ND) is widely regarded as one of the most virulent and destructive viral infections that create chaos in the poultry industry and cause widespread epidemics and consequentially debilitating economic losses on a global scale in terms of chicken products. The current experiment evaluates the protective effect of Glycyrrhiza glabra ( G. glabra) against the Newcastle disease virus (NDV) in chickens. Ninety (90) 1-day-old SPF chicks were treated according to ethical approval (BUFVTM 05-02-22) as follows (1) non-treated non-challenged control group; (2) NDV group: Challenged with genotype VII ND virus; and (3) LE/NDV group: Challenged with the virus and intermittently treated with powdered extract of G. glabra roots (LE) in drinking water (0.5 g/L) before and after viral challenge.

Result: The water medication of NDV-challenged chicks has resulted in a significant decrease in the severity of clinical symptoms, morbidity, and mortality rates, as well as the quantity of virus shed, compared with the NDV group. Treatment with LE has led to a significant reduction in serum ALT and AST activities, blood glucose level, urea, and creatinine, and significant restoration of serum proteins. In addition, the treatment has resulted in a decrease in MDA and NO levels, as well as an increase in T-SOD and catalase activities compared with untreated challenged chicks. LE decreased IFN-γ and TLR-3 gene expression in comparison with the NDV group. The treated challenged birds had fewer macroscopically detectable lesions in their respiratory, digestive, and lymphoid organs than the untreated challenged birds. Microscopically, the LE/NDV group exhibited mild to moderate pathological changes in the respiratory and digestive systems as well as lymphoid tissues, in contrast to the NDV group, which exhibited severe pathological changes. Furthermore, molecular docking assessment proved the efficacy of G. glabra against viral proliferation and invasion.

Conclusion: We concluded that Glycyrrhiza glabra powdered extract at a dose of 0.5 g/L drinking water can effectively mitigate the debilitating effects of Newcastle disease in chickens.