Immunostimulant effect of Egyptian propolis in rabbits.

The present experiment was conducted to study the effect of ethanolic extract of Egyptian propolis given alone or in combination with inactivated Pasteurella multocida vaccine on rabbits challenged with a virulent strain of Pasteurella multocida. Fifty-six New-Zealand rabbits, 6-8 weeks old and non-vaccinated against pasteurellosis, were randomly divided into eight equal groups. The first group was kept as a control for the experiment. The other groups received different treatments with propolis extract, inactivated vaccine, or both. The experiment continued for seven weeks during which clinical signs, body weight, and mortality rate were monitored, and blood samples were collected weekly for evaluating the leukogram, serum biochemistry, and immune response in all groups of animals. At the end of the seventh week, the animals were subjected to challenge with a virulent strain of Pasteurella multocida. Two weeks later, tissue specimens were collected from different organs for histopathological examination. Results showed that rabbits of the groups treated with both propolis and the vaccine by different routes appeared healthy after challenge. It has been concluded that alcoholic extract of propolis administrated in combination with inactivated Pasteurella multocida vaccine has no adverse effects on the general health conditions and enhances immune response in rabbits.

Effect of Egyptian propolis on cryptosporidiosis in immunosuppressed rats with special emphasis on oocysts shedding, leukogram, protein profile and ileum histopathology.

OBJECTIVES: To investigate the activity of Egyptian propolis extracts (ethanol and water) on cryptosporidiosis in experimentally infected dexamethasone-immunosuppressed rats. METHODS: A total of 180 male rats (190-220) g BWt were randomly divided into 9 equal groups (G1-G9). Groups of rats were kept as (G1): normal control, (G2-G9): immunosuppressed with dexamethasone and (G3-G9): infected with Cryptosporidium oocysts. Rats from (G4-G9) were given orally ethanol and water extract of propolis (at a dose of 50 mg/kg BWt) and nitazoxanide (standard anti-cryptosporidial drug at a dose of 100 mg/kg BWt) to infected rats with different regimes. Faecal pellets were collected from all groups to monitor oocysts shedding from the 2nd to the 15th day post infection. At the end of the experiment, blood was collected from all groups for determination of leukogram and serum proteins. Ileum specimens were also examined histopathologically. RESULTS: The highest reduction of oocysts shedding in faecal samples was 88% in rats prophylactically treated with propolis ethanol extract at the 4th dpi, and in rats prophylactically treated with water extract of propolis, was 91% at the 6th dpi. There was a marked increase in neutrophils count and α2- and ß-globulins levels in infected rats treated with both extracts, while a significant decrease was detected in lymphocytes compared to the infected non treated group. ß-Globulin level markedly increased in the rats administered nitazoxanide. Histopathological changes were observed in the ileum of rats infected with Cryptosporidium. CONCLUSIONS: Egyptian propolis extracts have an activity on cryptosporidiosis in rats. Moreover, propolis modulated the immunity in dexamethasone-immunosuppressed rats.

Use of allicin as feed additive to enhance vaccination capacity of Clostridium perfringens toxoid in rabbits.

The present study assessed the efficacy of Clostridium perfringens (C. perfringens) toxoid and/or allicin - as feed additive - in rabbits for preventing or minimizing the severity of infection with locally isolated strain of C. perfringens type A. Serum biochemical, immunological and pathological investigations were also done. One hundred rabbits of 6 weeks of age were divided into five equal groups (G1-G5). G1 were kept as normal control. G2 was allocated for C. perfringens type A infection. G3 was vaccinated with C. perfringens toxoid at zero time and then with a booster dose at the 3rd week of the experimental period. G4 was treated with allicin 20% added to the ration (200mg/kg ration) all over the experimental period. G5 was vaccinated with C. perfringens toxoid at the zero time then with a booster dose at the 3rd week of the experiment period, and treated with allicin 20% from the zero time till the end of the experiment. At the 4th week, G2, G3, G4 and G5 were challenged orally (5 ml) and subcutaneously (2 ml) with 24h cooked meat broth containing 1 × 10(7) colony-forming units/ml of C. perfringens type A strain. Blood and tissue samples were collected from all groups po st-vaccination then post-challenge for biochemical analysis, serum neutralization test and histopathological examinations. Results revealed that rabbits treated with both allicin and toxoid vaccine demonstrated high level of antitoxin titre post-challenge, improved liver and kidney functions, and reduced morbidity and mortality rates and the severity of histopathological changes associated with challenge of rabbits with C. perfringens type A strain. In conclusion, vaccination of rabbits with C. perfringens toxoid combined with allicin 20% gave better protection, enhanced immune response and had no adverse effects on the general health conditions against C. perfringens type A infection compared to rabbits vaccinated with C. perfringens toxoid only.

Protective effect of Egyptian propolis against rabbit pasteurellosis.

The present study was conducted to study the protective effect of ethanolic extract of propolis given subcutaneously (S/C) either alone or in combination with inactivated formalized Pasteurella multocida (P. multocida) vaccine in rabbits challenged with virulent P. multocida strain. Twenty-eight New-Zealand rabbits, 6-8 weeks old and not vaccinated against pasteurellosis, were randomly divided into four equal groups. Group (1) was kept as nonvaccinated control. Group (2) was injected S/C with propolis. Group (3) was vaccinated (S/C) with P. multocida vaccine only. Group (4) was injected with vaccine mixed with propolis as adjuvant. Groups (2, 3, and 4) received the same doses of propolis and vaccine after 4 weeks as a booster dose. The experiment continued for six weeks during which clinical signs, body weight, and mortality rate were recorded. Blood samples were collected every 2 weeks of treatment for evaluating the erythrogram and biochemical parameters. At the end of six weeks, all groups were subjected to challenge with a virulent strain of P. multocida. Two weeks later, tissue specimens were collected from different organs for histopathological investigation. Results showed that before challenge all rabbits of different groups were apparently healthy and had good appetite. After challenge, control group (1) showed acute form of the disease, 100% mortality rate, and severe histopathological changes. Rabbits of groups (2 and 3) showed less severe clinical signs, mortality rate, and histopathological changes than control. Rabbits of group (4) were apparently healthy with normal histological picture. In conclusion, an ethanolic extract of propolis injected alone or combined with formalized inactivated P. multocida vaccine improved general health conditions, liver and kidney functions in addition to reduction of the severity of adverse clinical signs, mortality rates, and histopathological changes associated with challenge of rabbits with P. multocida strain.

Some Haematological and Biochemical Investigations on Duck Virus Hepatitis following Administration of Glycyrrhizin.

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.

Antiviral and immune stimulant activities of glycyrrhizin against duck hepatitis virus.

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.