Immunological, biochemical and pathological effects of vitamin C and Arabic gum co-administration on H9N2 avian influenza virus vaccinated and challenged laying Japanese quails.

AIM: This study evaluated the effect of co-administration of vitamin C and Arabic gum (AG) supplements on the response of vaccinated (VAC) and challenged laying Japanese quails with avian influenza virus (AIV) H9N2. MATERIALS AND METHODS: One hundred and fifty 49-day-old laying Japanese quails were divided into 5 groups (G1-G5): the G1 group was a negative control, G2 group was unvaccinated + H9N2 challenged (Ch), G3 group was unvaccinated + supplements + Ch, G4 group was VAC + Ch, and the G5 group was VAC + supplements + Ch. The supplements (vitamin C, 1 g/liter of drinking water and AG, 1% ration) were given for 5 weeks post-vaccination (PV). The birds were injected subcutaneously with an inactivated H9N2 vaccine at 49 days of age. The quails were then challenged intranasally with AIV H9N2 at the 3rd week PV. Blood, tracheal swab and tissue samples were collected at the 1st, 2nd, and 3rd weeks PV, and at different time points post-challenge (PC). RESULTS: Growth performance, egg production (%), egg and eggshell weights, HI antibody titers, clinical signs, lesions, mortality, virus shedding rates, leukogram, biochemical and immunological parameters and histopathological lesions PC showed significant differences (P < 0.05) between the vaccinated-unsupplemented (G4) group and the vaccinated-supplemented (G5) group. G5 showed the highest (P < 0.05) growth performance, egg production, HI antibody titers, and heterophil phagocytic activity and the lowest heterophil/lymphocyte (H/L) ratio, mortality, virus shedding rates, creatinine level and histopathological lesion scores in the lungs. CONCLUSION: The co-administration of vitamin C and AG for 5 weeks can improve growth performance, egg production and the immune response in vaccinated laying quails challenged with AIV H9N2.

Immunostimulant effect of a mixed herbal extract on infectious bursal disease virus (IBDV) vaccinated chickens in the context of a co-infection model of avian influenza virus H9N2 and IBDV.

This study was conducted to assess the comparative effects of a mixed herbal extract (MHE) containing Ocimum sanctum, Withania somnifera, Emblica officinalis, Tinospora cordifolia, Mangifera indica, and Asphaltum (shilajit) on infectious bursal disease virus (IBDV)-vaccinated (VAC) chickens infected with IBDV and avian influenza virus (AIV) H9N2. The experiment included three groups (G1-G3): G1, the negative control group; G2, the VAC + challenged (Ch) group; and G3, the VAC + Ch + MHE group. MHE was orally administered continuously for 5 weeks post-vaccination (PV) with IBDV at 12 days of age, and the chicks were simultaneously challenged with virulent IBDV (intraocularly) and AIV H9N2 (intranasally) at 21 days PV. Blood and tissue samples as well as tracheal and cloacal swabs were gathered at different times PV and post-challenge. Immunological and haematological parameters, histopathological lesions, relative organ weights and final live weights revealed significant differences (P ≤ 0.05) between G2 and G3 groups. Furthermore, in the G3 group, the protection rates, ELISA and HI titers and CD4+/CD8+ ratio were significantly increased, whereas viral shedding titers and the heterophil/lymphocyte ratio were decreased. In conclusion, the oral administration of the mixed herbal extract for 5 weeks can stimulate the immune response to IBDV vaccination and relieves the pathogenicity of an AIV H9N2 and IBDV co-infection in chickens.

Effect of omega-3 rich diet on the response of Japanese quails (Coturnix coturnix japonica) infected with Newcastle disease virus or avian influenza virus H9N2.

This study was performed to evaluate the effects of omega-3 supplementation on growth performance, clinical signs, post-mortem lesions, haemagglutination inhibition (HI) antibody titres, gene expression and histopathology in quails (Coturnix coturnix japonica) infected with Newcastle disease virus (NDV) and avian influenza virus (AIV) H9N2. One hundred, 40-day-old male quails were divided into 5 groups: G1, fed a control basal diet; G2A, infected with NDV; G2B, infected with H9N2; G3A, infected with NDV and given omega-3, and G3B, infected with H9N2 and given omega-3. The dietary omega-3 supplementation was continued for 4 weeks: two weeks before infection and two weeks after intranasal infection with virulent NDV and AIV H9N2. Our results revealed significant differences (P < 0.05) in growth performance, HI antibody titres, clinical signs, post-mortem lesions, mortality, viral shedding rates, immunological parameters, and histopathological lesions between the treated (G3A and G3B) and untreated (G2A and G2B) groups. In conclusion, dietary omega-3 supplementation for 4 weeks can improve growth performance and alleviate the deleterious immunological and pathological effects of NDV and AIV H9N2 infection in quails.

Comparative immune response and pathogenicity of the H9N2 avian influenza virus after administration of Immulant®, based on Echinacea and Nigella sativa, in stressed chickens.

Avian influenza vaccines are commonly used in the poultry industry, and some medicinal plants can increase the efficacy of such vaccines. The objective of this study was to evaluate the effect of Immulant® (IMU) (a commercial product based on Echinacea and Nigella sativa) on stress induced by dexamethasone (DEX) in chickens vaccinated (VAC) against the H9N2 avian influenza virus (AIV-H9N2). Seven experimental groups were included: the negative control, VAC, DEX, VAC + DEX, VAC + DEX + IMU, VAC + IMU and IMU groups. The vaccinated chickens (at 10 days of age) were injected daily with DEX for three days pre-vaccination and for three days pre-challenge and orally administered 1% IMU for 6 weeks post-vaccination (PV). The chickens were then challenged intranasally with AIV-H9N2 at 28 days PV. Serum, blood, tracheal and cloacal swabs and tissue samples were collected in the 1st and 4th weeks PV and at different time points post-challenge. The results showed significant changes (P ≤ 0.05) in oxidative stress and antioxidant biomarkers (malondialdehyde, nitric oxide and reduced glutathione), haematological and immunological parameters, final live weights, relative organ weights and histopathological lesions between the VAC+DEX group and the VAC group. Moreover, IMU significantly increased protection rates post-challenge, HI antibody titers and heterophil phagocytic activity and decreased DEX-induced stress and virus shedding titers. In conclusion, oral administration of 1% IMU for six weeks can enhance the immune response after AI-H9N2 vaccination and reduce the pathogenicity of infection in stressed chickens.

Immunological and pathological effects of vitamin E with Fetomune Plus® on chickens experimentally infected with avian influenza virus H9N2.

Avian influenza virus (AIV) H9N2 infection causes economic losses on poultry farms, and immunostimulants are essential for improving chicken immunity. This study evaluated the immunological and pathological effects of vitamin E with Fetomune Plus® (a commercial product based on a yeast extract and vitamins) on chickens experimentally infected with AIV H9N2. Three groups of white Hy-Line chicks were included. The G1 group was kept as an uninfected untreated control, the G2 group was intranasally infected with the AIV H9N2 strain (0.5 ml of 106 50% egg infectious dose (EID50)), and the G3 group was infected and treated with vitamin E (200 mg/kg of diet) and Fetomune Plus® (1 ml/liter of drinking water) for four weeks. The gene expression of interferon-gamma (IFN-γ), interleukin (IL)-6, and IL-2 was determined at 3, 5 and 7 days post-infection (PI). Virus shedding titers and rates and haemagglutination inhibition (HI) antibody titers were detected. Clinical signs, mortalities and post-mortem lesions were recorded. The birds were weighed, and relative organ weights were calculated. Tissue specimens were taken for histopathological examination and immunohistochemistry (IHC). The expression of IFN-γ in the duodenum revealed a significant increase in G2 compared to G3 at 3 days PI, while the duodenal and splenic expression of IL-6 was significantly increased in G2 compared to G3 at 5 days PI. IL-2 was overexpressed in the duodenum in G3 compared to G2 at 3 and 5 days PI. A significant decrease (P ≤ 0.05) in the virus shedding titer and an increase in the HI titers were detected in G3 compared to G2. The clinical signs and the mortality rate were clearly appeared in G2 than in G3. By IHC, lower H9N2 staining intensity was observed in the examined organs from G3 than in those from G2. In conclusion, as a first report, vitamin E with Fetomune Plus® supplementation for four weeks could improve the immunological and pathological effects of H9N2 infection on chickens.