An evaluation of the impact of aloe vera and licorice extracts on the course of experimental pigeon paramyxovirus type 1 infection in pigeons

The progressive decrease in the efficiency of synthetic drugs has prompted research into phytogenic feed additives with potentially immunomodulatory and anti-infective properties. Complex diseases with a mixed etiology, including viral, pose a growing problem in domestic pigeons. The aim of this study was to determine the effectiveness of various doses of aloe vera and licorice extracts on the course of experimental PPMV-1 infection in pigeons. The experiment was performed on pigeons divided into 5 groups, including one control group and 4 experimental groups, which were orally administered aloe vera or licorice extracts at 300 or 500 mg/kg BW for 7 d after experimental inoculation with PPMV-1. On d 4, 7, and 14 after inoculation, cloacal swabs and samples of organs were collected from 4 birds in each group. The samples were analyzed to determine the copy number of PPMV-1 RNA by TaqMan qPCR. The results indicate that licorice and aloe vera extracts inhibited PPMV-1 replication by decreasing viral RNA copy numbers in the examined organs. The most inhibitory effect was observed in pigeons receiving aloe vera extract at 300 mg/kg BW, for which PPMV-1 RNA copy numbers were approximately 7-fold lower (brain), 9-fold lower (kidneys), and 14-fold lower (liver) than in the control group. The results of this study point to the potentially antiviral effects of aloe vera and licorice extracts in pigeons infected with PPMV-1. To the best of our knowledge, this is the first study to investigate the antiviral properties of aloe vera and licorice extracts in domestic pigeons.