ABSTRACT
The present study aimed to investigate the protective effect of glycyrrhizin (locally isolated and purified from licorice root) against duck hepatitis virus through the assessment of some hematological and biochemical parameters. One hundred and sixty white Pekin ducklings-one day old-were randomly divided into four equal groups. Group (1) was kept as normal control. Group (2) was inoculated I/P with 10 mg glycyrrhizin/kg BW, three times per week for four weeks. Group (3) was inoculated I/M with 0.5 ml of live attenuated DHV vaccine. Group (4) was inoculated with both glycyrrhizin (10 mg/kg BW I/P, three times per week for four weeks) and live attenuated DHV vaccine (0.5 ml, I/M). Then, all groups of treatment were challenged using virulent DHV except for 20 ducklings from the normal control group which were continued to be kept as negative control. The results revealed that duck hepatitis virus (DHV) caused macrocytic hypochromic anemia, leukopenia, hypoproteinemia, hypoalbuminemia, hyperglycemia, hypercholesterolemia, and marked elevation of liver enzymes and renal parameters. In conclusion, glycyrrhizin injected alone or in combination with DHV vaccine protected or ameliorated the deteriorating effects induced by DHV vaccine and/or duck hepatitis virus infection by improvement of erythrogram and leukogram, as well as liver and kidney functions.
ABSTRACT
This study was conducted to investigate the effect of glycyrrhizin as an immune stimulant against duck hepatitis virus (DHV). In vitro study was carried out to determine cytotoxic and antiviral effects of glycyrrhizin in VERO cells. In vivo study was performed on 40 one-day-old White Pekin ducklings. -and the birds weres divided into 4 groups: control, glycyrrhizin treated, vaccinated with live attenuated DHV vaccine and glycyrrhizin treated and vaccinated; to investigate the changes in immunity and challenge test. Blood samples were collected from each duckling for evaluation of cellular and humeral immunity. The in vitro results revealed that glycyrrhizin had antiviral and no toxic effects till 106 dilutions. Higher antibody titer was observed from the 5th week till the end of experiment in glycyrrhizin and vaccinated group. Treatment with glycyrrhizin alone or with DHV vaccine demonstrated a pronounced lymphocytic proliferation response after 4 days post-inoculation till the end of experiment, while vaccinated group revealed a pronounced proliferation response after 24 days post-inoculation. Treatment with glycyrrhizin alone or combination with DHV vaccine revealed good immune stimulant and antiviral effect against DHV.
