Serological response of chickens to oral vaccination with Newcastle disease virus

Conventional Newcastle disease vaccines are not suitable for application to village chickens in tropical countries of Asia. Trials with food-based vaccines are being initiated and the following experiments were performed to evaluate oral vaccination with Newcastle disease virus. Experimental chickens were vaccinated orally with the avirulent V4 strain of Newcastle disease virus and haemagglutination-inhibition antibody responses were measured. V4 virus was introduced into the crop by tube and total faecal output was collected daily and assayed for Newcastle disease virus. Virus was recovered on Days 5 and 6 after vaccination from most chickens that had received 10(7.4) and 10(6.4) 50% egg-infectious doses (EID50) of virus. There was no recovery of virus from birds receiving a lower dose of vaccine. Groups of chickens kept in cages with wire floors were given various doses of vaccine into the crop. Higher antibody titres were achieved with higher doses of virus. This dose responsiveness was not observed when various doses of vaccine were presented on food pellets and the groups of chickens were kept on concrete floors. Similar antibody responses were then seen with nominal doses of 10(5.2) and 10(8.2) EID50 per bird, possibly as a result of excretion and re-ingestion of the vaccine virus. Spread of the vaccine virus was demonstrated when control chickens and chickens receiving 10(7.7) EID50 of V4 virus on food pellets were housed together on a concrete floor. Similar antibody titres were achieved in both vaccinated and in-contact chickens.     

切除结膜结合淋巴组织鸡对新城疫疫苗点眼免疫反应Ⅱ.组织学与免疫组织化学研究

60只1日龄健康雏鸡随机分为A、B、C三组。A组于1日龄手术切除下眼睑结膜。A、B两组于12日龄时结扎鼻泪管，用新城疫克隆30苗点眼。C组为对照组。23日龄分别采取其CALT和哈德氏腺，比较观察其组织细胞。结果，1日龄手术切除下眼睑结膜后造成鸡CALT缺失，点眼免疫后，哈氏腺的免疫细胞也较正常免疫鸡少，而正常接种ND克隆30（B组）后，CALT发生早，生长快，淋巴细胞数量多，故本实验证实CALT对哈氏腺免疫细胞的数量与成分有一定的调控作用。CALT缺失鸡是研究黏膜免疫系统比较理想的模型。     

切除结膜结合淋巴组织鸡对新城疫疫苗点眼免疫反应 Ⅱ.组织学与免疫组织化学研究

60只 1日龄健康雏鸡随机分为 A、B、C三组。A组于 1日龄手术切除下眼睑结膜。A、B两组于 12日龄时结扎鼻泪管 ,用新城疫克隆 30苗点眼。C组为对照组。 2 3日龄分别采取其 CAL T和哈德氏腺 ,比较观察其组织细胞。结果 ,1日龄手术切除下眼睑结膜后造成鸡 CAL T缺失 ,点眼免疫后 ,哈氏腺的免疫细胞也较正常免疫鸡少 ,而正常接种 ND克隆 30 (B组 )后 ,CAL T发生早 ,生长快 ,淋巴细胞数量多 ,故本实验证实 CAL T对哈氏腺免疫细胞的数量与成分有一定的调控作用。 CAL T缺失鸡是研究黏膜免疫系统比较理想的模型     

Immune enhancing effects of Lactobacillus acidophilus on Newcastle disease vaccination in chickens

Introduction and purposeDespite the various vaccination programs for protection against New Castle disease, it remains an important threat to the poultry industry. The ability of the probiotic bacteria to improve the immune system in both animals and humans supports their use as immune adjuvants for vaccination. The aim of the present study was to examine the effects of Lactobacillus acidophilus in ND vaccination.Materials and methodsA total of 170 one day old chicks were divided in 5 groups. In groups A, B and C chicks were received L. acidophilus (5 × 10⁹, 3 × 10⁹ and 2 × 10⁹) and also vaccinated with inactivated and attenuated ND vaccines. In group D, chicks only vaccinated without bacterial inoculation and group E was negative control with neither vaccine nor bacteria. Then IgG and HI NDV antibody titers were measured in all tested groups.ResultsIgG and HI NDV antibody levels were significantly higher in Lactobacillus treated groups especially in group A with 5 × 10⁹ bacteria, than only vaccinated and negative control groups. Also antibody levels against NDV increased during the vaccination period especially in probiotic treated groups.ConclusionIn conclusion, L. acidophilus can use for improving immunogenicity of NDV vaccination programs.     

Laboratory evaluation of Newcastle disease vaccination programs for broiler chickens

Experiments were conducted to examine the efficacy of various commercial vaccination programs for the prevention of Newcastle disease (ND) in broilers. In all, chicks were from breeders vaccinated against ND via drinking water at 75-day intervals. Vaccination was by company personnel on company premises. In Expt. 1, the initial ND vaccination programs tested were vaccination at 1 day by coarse spray with the Spra-Vac machine or by tracheal instillation with the Beak-o-Vac machine, and vaccination at 7 days via drinking water. In Expts. 2-4, birds initially vaccinated via one of the three previously mentioned methods (Spra-Vac in Expt. 2, Beak-o-Vac in Expt. 3, and drinking water in Expt. 4) were revaccinated against ND by either drinking water or coarse spray with one of two commercial portable machines (ULVA Fan or Spray Master). Serologic and challenge data in Expt. 1 indicated that although broilers vaccinated by any of the three initial routes failed to produce measurable antibody to NDV, all methods resulted in protection against NDV challenge at 35 and 49 days. However, resistance to challenge with virulent ND was greatest in birds initially vaccinated by coarse spray with the Spra-Vac machine. Results in Expts. 2-4 indicated that NDV hemagglutination-inhibition titers were highest and resistance to challenge greatest in birds initially vaccinated at day 1 by coarse spray (Spra-Vac) and then revaccinated at 14 days by coarse spray. There were no differences, however, between the portable coarse spray machines in efficacy in reimmunizing broilers against NDV.     

The effect of dietary lysine excess and deficiency on metabolism in Japanese quail

We conducted three experiments with Japanese quail to study the influence of deficient and excessive contents of lysine in the feed in relation to certain zootechnical parameters, protein value, to the active of liver xanthine dehydrogenase, content of free plasma lysine under the conditions of the maximum saturation of blood pool, and to the changes in 14C-labelled lysine degradation. The zootechnical parameters and protein value were optimum at the content of 5.22 g Lys per 16 g nitrogen in the feed, the activity of liver xanthine dehydrogenase was maximum. In a separate experiment the maximum saturation of blood pool determined with respect to a lysine supply in the feed reached the highest value at 6.88 g Lys per 16 g nitrogen and it decreased later on although the lysine supply increased. We assume the existence of a regulating mechanism that does not allow exceeding certain lysine concentrations in the blood plasma. Lysine degradation measured by the value of 14CO2 expired from 14C-labelled lysine was higher both with lysine deficient and excessive content, than with the lysine content in the feed approaching the required value.     

The effect of parental immunity on the response of five-days-old chicks to intranasal vaccination with F strain Newcastle disease virus

Summary Two flocks of chicks from parents not immune to Newcastle disease (ND) virus and six flocks from immune parents were vaccinated intranasally with 10^6.03 to 10^6.86 mean embryo infective doses of F strain ND virus on the fifth day of life. A group of chicks from each flock was left unvaccinated. Vaccinated and unvaccinated chicks from each flock were killed on days one to ten and then every other day until 39 to 61 days. Serums were examined by the ND virus haemagglutination-inhibition (HI) test, and tissues were inoculated into fertile hens' eggs for recovery of vaccine virus. Vaccine virus was recovered from vaccinated nonparentally-immune chicks daily from two to 14 days post-vaccination. Their serological response was detectable two days post-vaccination and reached peak levels nine to 14 days post-vaccination. In contrast, vaccine virus was recovered rarely or not at all from parentally-immune chicks and their serological response was much less than in chicks with no parental immunity. It is concluded that parentally-acquired antibodies neutralised vaccine virus so reducing the amount of immunizing virus antigen to which the host was exposed.

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Sumario Dos lotes de pollos de padres no inmunes a la enfermedad de Newcastle y seis lotes de pollos de padres inmunes fueron vacunados instranasalmente con 10^6.08 a 10^6.86 dosis infectantes medias para embriones de la cepa F del virus de Newcastle, el dia quinto despues del nacimiento. Un grupo de pollitos de cada lote fue dejado sin vacunar. Pollos vacunados y no vacunados de cada lote fueron sacrificados desde el dia primero hasta el dia décimo despues de la vacunación y luego dejando un dia hasta los dias 39 a 61. Los sueros fueron examinados por la prueba de la inhibición de la hemaglutinación del virus de Newcastle y los tejidos fueron inoculados en huevos fértiles de gallina con el fin de recobrar el virus vacunal. El virus vacunal fue recobrado de pollitos vacunados sin inmunidad parental desde el dia dos hasta el dia 14 despues de la vacunación. La respuesta serológica de los pollos fue detectable dos dias despues de la vacunación y alcanzó los niveles mas altos del noveno al catorceavo dia. En contraste, el virus vacunal se recobró muy raramente ó no se recuperó de pollos con immunidad parental y sus respuestas serológicas fue mucho menor que en pollitos sin inmunidad parental. Se concluye que los anticuerpos adquiridos pasivamente neutralizaron al virus vacunal reduciendo así la cantidad de antígeno viral inmunizante a la que el huesped se había expuesto.

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Résumé 2 bandes de poussins issues de parents non immuns au virus de la maladie de Newcastle et 6 autres bandes issues de parents immuns furent vaccinés par la voie nasale au 5ème jour de leur vie avec 10^6.08 à 10^6.086 doses moyennes infectantes pour l'embryon de la souche F du virus de Newcastle. Dans chaque bande, un groupe de poussins fut laissé non vacciné. Des poussins de chaque bande, vaccinés et non vaccinés, furent sacrifiés chaque jour, du jour 1 au jour 10 et ensuite du jour 39 jusqu'au jour 61. Leurs sérums furent examinés au moyen du test d'inhibition de l'hémagglutination et leurs tissus furent inoculés à des oeufs de poules embryonnés pour essayer de retrouver le virus vaccinal. Celui-ci fut décelé du 1er au 14ème jour après la vaccination chez les poussins vaccinés et issus de parents non immuns. Leur réponse sérologique était décelable 2 jours après la vaccination et atteignait son niveau maximum du 9ème au 14ème jour après cette vaccination. Au contraire le virus vaccinal n'était retrouvé que rarement ou pas du tout chez les poussins à immunité parentale et la réponse sérologique de ces derniers était bien moindre que celle des poussins sans immunité transmise. On en conclut que les anticorps d'origine parentale neutralisent le virus vaccinal, réduisant ainsi la quantité d'antigène viral immunisant par laquelle l'organisme est sollicité.

     

Effect of vitamin A deficiency on the activity of macrophages in Newcastle disease virus-infected chickens

The effect of vitamin A deficiency on the activity of peritoneal macrophages (PM) was investigated in noninfected and Newcastle disease virus (NDV)-infected chickens. Day-old chickens with limited vitamin A reserves were fed diets containing either marginal (120 retinol equivalents (RE)/kg) or adequate (1200 RE/kg) levels of vitamin A. At 4 weeks of age, half of the chickens in each group were infected with the La Sota strain of NDV and PM were isolated 11 or 12 days later. These were used for counting the uptake of fluorescein isothiocyanate-labeled yeast cells as an indicator of phagocytic activity and for measuring the reduction of nitroblue tetrazolium (NBT), which provides an estimate of oxygen-dependent killing of microorganisms. Vitamin A deficiency impaired NBT reduction and, to a lesser extent, phagocytosis in both infected and noninfected chickens. NDV infection increased phagocytosis and NBT reduction in normal and, to a lesser extent, in vitamin A-deficient chickens.     

Consequence of Cryptosporidiosis on the immune response of vaccinated broiler chickens against Newcastle disease and/or avian influenza

The consequence of cryptosporidiosis on the immune response of vaccinated chickens against Newcastle disease and/or avian influenza was studied by using 240, 1 day old, male, white Hy-Line chicks and divided into 8 groups and subgroups. Each group or subgroup was consisting of 30 chicks (15?×?2 replicates). The first and second groups were kept as unvaccinated control, G1uninfected and G2 infected. G3, G4 and G5 contained 2 subgroups A&B (G3A, G3B, G4A, G4B, G5A and G5B). Chicks of subgroup A were vaccinated only while chicks of subgroup B were infected and vaccinated. These chicks were orally inoculated with 5?×?10⁵ oocysts of Cryptosporidium baileyi (C. baileyi) at 2 days of age. Chickens were vaccinated intraocular with live Newcastle disease (ND) vaccine (Hitchner on day 7th and LaSota on day 17th of chicken life) (G3) or vaccinated by subcutaneous route with Volvac®- H5N2- AI vaccine on day 10 of chicken life (G4). Last group (G5) was infected similarly and vaccinated with ND and AI vaccines with the same day, dose and route of vaccination for each one. Random blood samples were collected for 3 weeks post-vaccination for investigation of humoral immune response against Newcastle and/or avian influenza vaccines by the haemagglutination inhibition (HI) test. The results showed that H5N2 vaccine at day 10 of chicken life is effective in chickens indicated by the geometric mean of HI titer against AI virus. The findings of this study showed that the infection with Cryptosporidia in the broiler chicken has a depressive effect on the immune status of the birds vaccinated against ND and/or AI vaccination. Moreover, the obtained protection rates against challenge with virulent ND virus observed to be parallel to the results of HI- test. Also, by using 2 different antigens (one commercial and field prepared antigen) to avian influenza virus, lower Geometric mean (GM) HI titer were appeared in infected and vaccinated group than vaccinated group only. A study of the relative lymphoid organs weight such as bursa of Fabricius from the experimental chicks indicated that those organs were comparable between the groups infected-vaccinated and vaccinated only. Non significant variations in final live weight between uninfected control and infected groups were indicated. Also, H5N2-AI vaccination at 10 days old did not affect the final live weight. ND and/or AI Vaccination could not be a substitute to application of good hygienic measures and fecal examination of the birds especially for protozoal diseases such as cryptosporidiosis. It could be concluded that cryptosporidiosis could be one cause of ND and/or AI vaccination failure in poultry farms.     

Natural infection of broiler breeder chickens with endemic apathogenic Newcastle disease virus and their subsequent response to vaccination with a live V4 Newcastle disease virus vaccine

Flocks of broiler breeder chickens housed on a commercial farm were monitored from 13 w of age for natural infection with endemic lentogenic Newcastle disease virus (NDV). Seroconversion was first detected at 17 w. By 24 w, all 8 flocks had achieved peak log2 mean haemagglutination inhibiting antibody titres of up to 4.8. Antibody titres then declined and rose again over several months, suggesting cyclic reinfection with NDV. A lentogenic NDV indistinguishable from V4 was isolated from the cloaca of one bird at 18 weeks of age. At 54 weeks of age, 6 of 8 flocks were vaccinated en masse with live V4 NDV vaccine, 3 flocks by drinking water and 3 flocks by aerosol. All flocks were serologically monitored for a further 8 w. Drinking water vaccination induced an anamnestic response in 3 flocks, showing that flocks with pre-existing active immunity to NDV may be successfully vaccinated with V4. However, in all aerosol vaccinated flocks, the procedures failed to induce a response different to that observed in unvaccinated flocks. The serological response to vaccination was greater in sires than in dams.     

Efficacy of mannanoligosaccharides and humate on immune response to Avian Influenza (H9) disease vaccination in broiler chickens

The effect of mannanoligosaccharides (MOS) and Humate (HU) in broiler diets on antibody titers against Avian Influenza virus (AIV) was evaluated. A completely randomized experimental design was used, and chicks were divided into 8 treatment groups, with 4 replicates per treatment and 10 chicks per replicate. Treatments were: 1) negative control group (CTL−), neither vaccinated against AIV nor given additives; 2) positive control (CTL+) or broilers were vaccinated against AIV + 0 additives; 3,4 and 5) CTL+ plus diet supplemented with 0.1, 0.2 and 0.3% HU, respectively; 6,7 and 8) CTL+ plus diet supplemented with 0.1, 0.2 and 0.3% MOS, respectively. For antibody analyses, blood samples were weekly collected by wing veins and the titers of antibody against AIV were measured by haemagglutination-inhibition test (HI). Compared to the positive control, the antibody titers against AIV were determined significantly lower in negative control group from 28 to 42 days of age. The inclusion of MOS resulted in increased antibody titers against AIV in the fourth, fifth and sixth weeks of age. MOS was effective in stimulating the humoral immune responses against AIV vaccine viruses. This study demonstrated an increase in the antibody titers in broilers fed diets containing 0.3% HU. In general, results of this study demonstrated that MOS proved to be much more effective on antibody production against AIV in broiler chicks than HU. Immune function could be modified with dietary HU and MOS supplementation.     

黄芪、白术水煎剂对鸡新城疫疫苗免疫效果的影响

探讨鸡口服黄芪、白术水煎剂对鸡新城疫疫苗免疫效果的影响。给7日龄健康梅岭土鸡连续7 d饮用口服黄芪或白术水煎剂,12.5 g/kg.d,后分2次间隔14 d滴鼻接种鸡新城疫Ⅳ系弱毒苗(LaSota株)。分别在首免前、及免疫后1、2、3、4周采血,分离血清,用血凝抑制试验检测鸡新城疫抗体效价(HI)。结果显示,口服中药组的鸡血清HI效价高于未服中药对照组,黄芪水煎剂组于二免后1周,白术水煎剂组于二免后1、2周,HI效价显著高于未服中药对照组。结果表明,在疫苗免疫之前给鸡口服白术水煎剂或黄芪水煎剂可以显著增强免疫效果。