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In this study, the impact of varying dietary zinc (Zn) and copper (Cu) levels on the growth, immunological response, and skeletal health of developing turkey poults was investigated. For 0-4 and 5-8 weeks of age, respectively, three Zn levels of 50, 70, and 90 mg/kg and 45, 65, and 85 mg/kg were employed. Three Cu levels, namely 8, 12, and 16 mg/kg for 0-8 weeks of age, were also utilized. There were 288 (9 × 4 × 8) day-old turkey poults with equal body weight that were randomly assigned to 9 treatments, each consisting of 4 replicates and 8 poults per replicate. In comparison to other dietary combinations, there was a significant (P ≤ 0.05) increase in body weight gain observed in the 90 and 85 mg Zn/kg with 16 mg Cu/kg diet during 0-4 and 0-8 weeks of age, respectively, and the 70 and 65 mg Zn with 16 mg Cu /kg diet during 0-4 and 0-8 weeks of age, respectively. When compared to low levels of zinc in the diet at 5-8 and 0-8 weeks of age, respectively, feed conversion ratio was shown to be significantly (P ≤ 0.01) better with 90 and 85 mg Zn/kg diet. In a similar pattern, feed utilization efficiency was considerably (P ≤ 0.01) higher at 16 mg Cu/kg diet than it was at lower Cu levels in the diets given to the animals over the 0-4 week period. Compared to other dietary combinations, there was a substantial (P ≤ 0.01) improvement in cell-mediated immune response (foot web index to PHAP) and humoral immune response (HA titer to SRBC) when 85 mg zinc and 16 mg copper/kg diet was consumed at 0-4 and 5-8 weeks of age. At greater dietary Zn and Cu levels than its lower values, the weight of the spleen and thymus was considerably (P ≤ 0.05) higher. In a dietary combination of 90 mg Zn with 16 mg Cu/kg during 0-4 and 85 mg Zn with 16 mg Cu/kg diet during 5-8 weeks of age, respectively, there were significantly (P ≤ 0.05) greater bone width (proximal and distal), tibia bone ash, calcium, and phosphorus detected respectively. Significantly (P ≤ 0.01) greater Zn and Fe contents were found in the tibia bone at 90 and 85 mg Zn/kg diet, respectively, compared to values obtained at other Zn levels in the diet throughout 0-4 and 5-8 weeks of age. During the first 8 weeks of life, a diet containing 12 mg of copper per kilogram was shown to have a significantly (P ≤ 0.05) increased Zn and Fe content in the tibia bone compared to other levels. It is possible to draw the conclusion from the data that, for growing turkey poults, dietary combinations of 90 mg Zn/kg with 16 mg Cu/kg diet and 85 mg Zn with 16 mg Cu/kg diet between 0 and 4 and 5-8 weeks of age, respectively, were sufficient for optimum development, immunity, and skeletal health indices., Competing Interests: Declarations. Ethics Approval: The care and use of experimental animals were conducted in accordance with all institutional and national norms. Competing Interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The common avian origin of many zoonotic infections and epidemics warrants investigation into the mechanism of respiratory surface protection in reservoir species such as birds. Our recent molecular investigations on the evolution and pulmonary expression of an ancient family of proteins, the C-type lectins, have revealed unique molecular adaptations in the surfactant proteins avian SP-A1 (aSP-A1), aSP-A2 and aSP-C coupled with the loss of surfactant protein-D (SP-D) in the avian lineage. As surfactant proteins are members of the collectin family, a subgroup of the C-type lectins, an in silico search for related non-surfactant collectin proteins (Collectin-10 (CL-10) and Collectin-11 (CL-11)) in the NCBI genome database was conducted to understand their evolution in the avian lineage. In addition, both CL-10 and CL-11 gene expression in the lungs and other organs of zebra finches and turkeys was confirmed by PCR. These PCR-confirmed zebra finch and turkey CL-10 and CL-11 sequences were compared with sequenced and in silico -predicted vertebrate homologues to develop a phylogenetic tree. Compared with avian surfactant proteins, CL-10 and CL-11 are highly conserved among vertebrates, suggesting a critical role in development and innate immune protection. The conservation of CL-11 EPN and collagen domain motifs may compensate to some extent for the loss of SP-D in the avian lineage.This article is part of the theme issue 'The biology of the avian respiratory system'.

Histomonas meleagridis, a protozoan parasite responsible for histomonosis (syn. Blackhead disease, histomoniasis), presents an increasing challenge for poultry health, particularly with the ban of licensed prophylactic and treatment options. Recent studies have explored H. meleagridis proteome, exoproteome, and surfaceome, linking molecular data to virulence and in vitro attenuation. Nevertheless, proteins involved in interactions with hosts remain largely unknown. In this study, we conducted immunoproteome analyses to identify key antigens involved in the humoral immune response of the parasite's main hosts, turkeys and chickens. Immunogenic proteins were isolated via immunoprecipitation using sera from chickens and turkeys that were vaccinated with a single attenuated strain and challenged with virulent strains of the protozoan, respectively. Mass spectrometry identified 155 putative H. meleagridis immunogenic proteins, of which 43 were recognized by sera from both hosts. In silico antigenicity screening (VaxElan) identified 33 pan-reactive antigens, with VaxiDL further highlighting 10 as potential vaccine candidates. Comparative analysis revealed host-specific immune responses, with 16 differential immunogenic proteins in chickens (6 specific to virulent and 10 to attenuated preparations) and 19 unique proteins in turkeys, all associated with virulent strains. These results enhance our understanding of H. meleagridis immunogenic protein dynamics and host-pathogen specificities, supporting the development of improved diagnostic tools and potential protective measures against the infection., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Weekly artificial insemination (AI) is a common practice on commercial turkey breeder farms. The aim of this study was to determine changes in stress as well as oviduct and systemic immunity in response to weekly artificial inseminations through the laying cycle of turkey hens. Hens were divided into sham (extender only) and semen (extender + sperm) treatments. Blood, uterovaginal junction (UVJ), vagina, and spleen were collected at start of lay, peak lay, and end of lay (n = 8-12 /group for blood and 5 for tissues). The heterophil to lymphocyte ratio (H:L) was significantly higher in the semen-inseminated hens compared with the sham-inseminated hens at peak lay (n = 0.05). Immunohistochemistry revealed a higher number of CD3+ T cells in sperm storage tubules (SSTs) and UVJ submucosa at the end of lay compared with start and peak of lay across insemination treatments (n = 0.07 and 0.01, respectively). Within the end-of-lay group, semen-inseminated hens showed a higher number of CD3+ T cells in SSTs and UVJ submucosa (n = 0.04 and 0.1, respectively). The number of IgM+ B cells was significantly higher at start of lay compared with end of lay in SSTs and spleen (n = 0.01 and 0.0001, respectively) regardless of insemination treatment. In the vaginal submucosa, the number of IgM+ B cells was significantly higher in the semen group compared with the sham group at peak lay (n = 0.04). The number of IgA+ and IgY+ B cells were higher in the UVJ submucosa at the end of lay compared with start of lay, regardless of insemination treatment (n = 0.0001 and 0.03 respectively). In summary, the localization and number of adaptive immune cells change in response to the presence of sperm and laying cycle and depend on factors including immune cell type and tissue compartment. This suggests that the adaptive immune system of the oviduct plays an important role in responding to sperm based on the stage of the laying cycle. Modulating this immune response could improve reproductive performance., Competing Interests: Declaration of competing interest The author BW and MS are employed by the company Select Genetics. The remaining authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier Inc.)

Clostridial dermatitis (CD), caused by Clostridium septicum, is an emerging disease of increasing economic importance in turkeys. Currently, there are no effective vaccines for CD control. Here, two non-toxic domains of C. septicum alpha toxin, namely ntATX-D1 and ntATX-D2, were identified, cloned, and expressed in Escherichia coli as recombinant subunit proteins to investigate their use as potential vaccine candidates. Experimental groups consisted of a Negative control (NCx) that did not receive C. septicum challenge, while the adjuvant-only Positive control (PCx), ntATX-D1 immunization (D1) and ntATX-D2 immunization (D2) groups received C. septicum challenge. Turkeys were immunized subcutaneously with 100 μg of protein at 7, 8 and 9 weeks of age along with an oil-in-water nano-emulsion adjuvant, followed by C. septicum challenge at 11 weeks of age. Results showed that while 46.2% of birds in the PCx group died post-challenge, the rate of mortality in D1- or D2-immunization groups was 13.3%. The gross and histopathological lesions in the skin, muscle and spleen showed that the disease severity was highest in PCx group, while the D2-immunized birds had significantly lower lesion scores when compared to PCx. Gene expression analysis revealed that PCx birds had significantly higher expression of pro-inflammatory cytokine genes in the skin, muscle and spleen than the NCx group, while the D2 group had significantly lower expression of these genes compared to PCx. Peripheral blood cellular analysis showed increased frequencies of activated CD4+ and/or CD8+ cells in the D1 and D2-immunized groups. Additionally, the immunized turkeys developed antigen-specific serum IgY antibodies. Collectively, these findings indicate that ntATX proteins, specifically the ntATX-D2 can be a promising vaccine candidate for protecting turkeys against CD and that the protection mechanisms may include downregulation of C. septicum-induced inflammation and increased CD4+ and CD8+ cellular activation., Competing Interests: US Provisional Patent Nos. 63/609,022, 63/608,491, 63/597,112 titled "Vaccine Composition Against Clostridial Dermatitis". This does not alter our adherence to PLOS ONE policies on sharing data and materials.The sequences of ntATX-D1 and ntATX-D2 vaccine antigens reported in this work are also deposited in the GenBank (https://www.ncbi.nlm.nih.gov/nuccore/PP003322 and https://www.ncbi.nlm.nih.gov/nuccore/PP003323)., (Copyright: © 2024 John et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Across the world, many commercial poultry flocks and captive birds are threatened by infection with Aspergillus fumigatus. Susceptibility to aspergillosis varies among birds; among galliform birds specifically, morbidity and mortality rates seem to be greater in turkeys than in chickens. Little is known regarding the features of avian immune responses after inhalation of Aspergillus conidia, and to date, scarce information on inflammatory responses during aspergillosis exists. Thus, in the present study, we aimed to improve our understanding of the interactions between A. fumigatus and economically relevant galliform birds in terms of local innate immune responses. Intra-tracheal aerosolization of A. fumigatus conidia in turkey and chicken poults led to more severe clinical signs and lung lesions in turkeys, but leukocyte recovery from lung lavages was higher in chickens at 1dpi only. Interestingly, only chicken CD8+ T lymphocyte proportions increased after infection. Furthermore, the lungs of infected chickens showed an early upregulation of pro-inflammatory cytokines, including IL-1β, IFN-γ and IL-6, whereas in turkeys, most of these cytokines showed a downregulation or a delayed upregulation. These results confirmed the importance of an early pro-inflammatory response to ensure the development of an appropriate anti-fungal immunity to avoid Aspergillus dissemination in the respiratory tract. In conclusion, we show for the first time that differences in local innate immune responses between chickens and turkeys during aspergillosis may determine the outcome of the disease., (© The Author(s) 2020. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.)

The re-emerging disease histomonosis is caused by the protozoan parasite Histomonas meleagridis that affects chickens and turkeys. Previously, protection by vaccination with in vitro attenuated H. meleagridis has been demonstrated and an involvement of T cells, potentially by IFN-γ production, was hypothesized. However, comparative studies between chickens and turkeys on H. meleagridis-specific T cells were not conducted yet. This work investigated IFN-γ production within CD4 + , CD8α + and TCRγδ + (chicken) or CD3ε + CD4 - CD8α - (turkey) T cells of spleen and liver from vaccinated and/or infected birds using clonal cultures of a monoxenic H. meleagridis strain. In infected chickens, re-stimulated splenocytes showed a significant increase of IFN-γ + CD4 + T cells. Contrariwise, significant increments of IFN-γ-producing cells within all major T-cell subsets of the spleen and liver were found for vaccinated/infected turkeys. This indicates that the vaccine in turkeys causes more intense systemic immune responses whereas in chickens protection might be mainly driven by local immunity., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Nucleocapsid (N) protein is the most highly expressed of all avian metapneumovirus (aMPV) viral proteins and stimulates a substantial immune response in infected animals. Codon optimized recombinant N (rec-N) protein from aMPV subtypes A, B, and C were expressed using the baculoviral expression system in Trichoplusia ni (Tni) insect cells. A mixture of purified rec-N antigens from each subtype was used as a coating antigen and was evaluated in indirect ELISA (iELISA) to assess antibody response in serum samples collected from experimentally infected chickens and turkeys with different aMPV subtypes. Also, archived field serum samples that were collected from different poultry submissions were used. Receiver operating characteristic (ROC) analysis was performed using chicken and turkey serum samples that were confirmed by indirect fluorescent antibody (IFA) test for serostatus (positive n = 270, negative n = 610). The ROC analysis showed sensitivity and specificity of 97 % at a cut-off value of 0.25. The rec-N iELISA was compared with a commercial whole virus-based APV kit. The rec-N iELISA showed comparable results in detecting antibody response in aMPV infected chicken sera but was more sensitive in detecting early antibody response in aMPV infected turkey serum samples. Our results further confirm the presence of aMPV antibodies in Canadian domestic poultry populations. The developed aMPV-rec N iELISA offers a safe and valuable alternative to whole virus-based iELISA for serodiagnosis and seroepidemiological surveillance of the disease in domestic poultry., (Copyright © 2020. Published by Elsevier B.V.)

Among the different vaccines used to control highly pathogenic avian influenza, an HVT vector-based live recombinant avian influenza vaccine, expressing the haemagglutinin gene of an H5N1 HPAI virus, has been used by the poultry industry since 2012. The objective of the study presented in this paper was to test the efficacy of the commercially available HVT-based recombinant H5 vaccine against antigenically drifted H5N1, H5N8 and H5N2 HPAI virus circulating in Egypt recently. Groups of SPF chicks vaccinated at day-old with the HVT-based recombinant H5 vaccine were challenged, along with non-vaccinated controls, with 10 6 EID 50 each of H5N1, H5N2 or H5N8 HPAI virus at 28 days of age. The birds were monitored for clinical protection and virus shedding during a 10-day postchallenge period. Clinical protection levels were 90%, 90% and 80% following challenge with the H5N1, H5N2 and H5N8 field isolates, respectively. Challenge virus shedding was significantly reduced in vaccinated groups, with up to 40%, 30% and 20% of non-shedders, and 3.8, 3.3 and 2.8 log 10 reduction in the amount of excreted virus following challenge with H5N1, H5N2 and H5N8 viruses, respectively. Analyses of the amino acid sequences of the HA proteins of challenge viruses and serological relatedness with the vaccine insert revealed significant antigenic divergences between the vaccine and the challenge viruses. These results provide further evidence of the potential of HVT-based recombinant H5 vaccine to provide cross-protection against antigenically drifted HPAI H5Nx viruses with strong control on virus shedding.

We postulated that the use of appropriate levels and proportions of arginine (Arg) and methionine (Met) in compound feed with high lysine content (Lys) would make it possible to fully exploit the growth potential of modern fattening turkey crossbreds, without compromising their immune system. The aim of this study was to determine the effect of different ratios of Arg and Met in diets with high Lys content on the performance and immune status of turkeys. The turkeys were assigned to 6 groups with 8 replicates per group and 18 birds per replicate. Six feeding programs, with 3 dietary Arg levels (90, 100, and 110%) and 2 dietary Met levels (30 and 45%) relative to dietary Lys content, were compared. During each of 4 feeding phases (weeks 0-4, 5-8, 9-12, and 13-16), birds were fed ad libitum isocaloric diets containing high level of Lys, approximately 1.83, 1.67, 1.49, and 1.20%, respectively. The dietary treatments had no effect on daily feed intake or body weight at any stage of the study. The protein content of the breast meat was higher in the treatments with the highest Arg level (110%) compared with the lowest Arg level (90%). Similarly, protein content was higher in the treatments with the higher Met level compared with the lower Met level. Higher plasma levels of tumor necrosis factor, interleukin 6 (IL-6), and immunoglobulin Y were found in turkeys fed diets with the lowest Arg content. An increase in Met content resulted in a decrease in plasma content of IL-6. In growing turkeys fed diets high in Lys, an Arg level of 90% relative to Lys can be used without negatively affecting production results and immune system. Regardless of dietary Arg levels, an increase in Met content does not stimulate the immune defense system and shows no effect on growth performance of turkeys in current trial., (Copyright © 2020. Published by Elsevier Inc.)

The research hypothesis postulated that the optimal dietary inclusion levels and ratios of lysine (Lys), arginine (Arg), and methionine (Met) can increase the growth potential of hybrid turkeys and limit metabolic disorders that weaken immune function. The experiment was carried out in a full rearing cycle, from 1 to 16 wk of age, in a two-factorial randomized design with 3 levels of Arg and 2 levels of Met (90, 100 and 110% of Arg, and 30 or 45% of Met, relative to the content of dietary Lys), with 6 groups of 8 replicates per group and 18 turkeys per replicate. In the first and second month of rearing, a significant dietary Arg-by-Met interaction was noted for daily feed intake and body weight gain, and a more beneficial effect was exerted by higher Met content and medium Arg content. Throughout the experiment, the higher dietary Met level increased the final body weight (BW) of turkeys (P = 0.001). Different dietary Arg levels had no influence on the growth performance of turkeys, but the lowest level decreased dressing yield (P = 0.001), and the highest level increased the percentage of breast muscles in the final BW of turkeys (P = 0.003). The lowest Arg level (90% of Lys content) undesirably increased the concentration of the proinflammatory cytokine IL-6 (P = 0.028) and decreased globulin concentration (P = 0.001) in the blood plasma of turkeys. The higher dietary Met level (45% of Lys content) increased plasma albumin concentration (P = 0.016). It can be concluded that higher dietary levels of Met (45 vs. 30% of Lys content) and Arg (100 and 110 vs. 90% of Lys content) have a more beneficial effect on the growth performance and immune status of turkeys., (Copyright © 2019. Published by Elsevier Inc.)

The effect of embryonic thermal manipulation on the post-hatch immune response to a lipopolysaccharide (LPS) challenge was studied in Pekin ducklings and turkey poults. Commercial duck and turkey eggs were distributed among four treatments: SS-Control (37.5 °C from embryonic day [ED] 1 to 25); SS-LPS (37.5 °C from ED1 to 25 + LPS at D0 [hatch]); HH-LPS (38 °C from ED1 to 25 + LPS at D0; SH-LPS (37.5 °C from ED1 to 10 and 38 °C from ED 11 to 25 + LPS at D0). At ED16 and ED24, the egg shell temperature of the duck and turkey eggs in the HH and SH treatments were higher (P ≤ 0.01) than the SS treatment. Ducklings and poults in the HH treatment had the lowest yolk free body weight at hatch (P ≤ 0.05). At 24, 48, and 72 h post-LPS injection, ducklings and poults in the HH-LPS treatment had significantly reduced BW compared with the SS-Con treatments (P ≤ 0.05). Ducklings and poults in the SH-LPS and HH-LPS treatments had increased plasma heat shock protein 70 (HSP70) and lower splenic HSP70 mRNA amounts than the SS-LPS treatments at 24, and 48 h post-challenge (P ≤ 0.05). At 48 and 72 h, macrophage nitric oxide (NO) production in ducklings and poults in the SH-LPS and HH-LPS treatments was lower than in the SS-LPS treatments (P ≤ 0.05). Ducklings and poults in the SH-LPS treatment had increased thymocyte proliferation compared to the SS-LPS treatment at 24, 48 and 72 h (P ≤ 0.05). At 24 h, ducklings in the SH-LPS treatment had increased splenic IL-10 and reduced IFNγ and IL-6 mRNA abundance. However, both ducklings and poults in the HH-LPS treatment had increased IFNγ, and IL-10 mRNA abundance compared to the SS-LPS treatment (P ≤ 0.05). At 48 h, SH-LPS ducklings and poults had lower splenic IL-10 mRNA abundance (P ≤ 0.05) while the HH-LPS treatment resulted in comparable splenic IL-10 mRNA compared to the SS-LPS treatment (P ≥ 0.05). Ducklings and poults in the SH-LPS treatment had increased thymic and splenic CD8 + /CD4 + ratios at 24 h versus the SS-LPS treatment (P ≤ 0.05). In conclusion, embryonic thermal manipulation from ED11-25 increased extracellular HSP70 release, thymocyte proliferation and IL-10 but decreased splenic HSP70 and IFNγ mRNA amounts at 24 h post-LPS injection. This suggests that mild heat stress during the later stages of incubation could potentially prime the embryonic immune system thereby enhances the immune response as earlier than 24 h to eliminate the inflammatory response without affecting the growth performance by increase the extracellular release of HSP70 in both ducklings and poults. Continuous exposure to the small increase in temperature from ED 1-25 (HH) caused an imbalance between pro (IFNγ)- and anti-inflammatory cytokines(IL-10) which affects hatchling responses to an inflammatory challenge and increased mortality. The amount of extracellular HSP70 could potentially play an important role in modulating the immune response against inflammatory challenges., (Copyright © 2019. Published by Elsevier Ltd.)

Background: Haemorrhagic enteritis (HE) of turkeys was first described in 1937 in the USA, while in Poland it was first diagnosed in 1987. Polish haemorrhagic enteritis virus (HEV) isolates are usually low pathogenic and trigger a subclinical disease. Unfortunately, even the low- pathogenic HEV strains cause severe immunosuppression leading to secondary bacterial infections and huge economic losses. The objective of this study was to evaluate if the influence of Met on HEV infected turkeys immune response can be differentiated by both its level and source. Met is one of the amino acids that not only play a nutritional role but also participate in and regulate key metabolic pathways and immune response. In our study, the birds were assigned to 4 dietary treatments which differed in Met levels (0.55 and 0.78% in weeks 1-4 of age and 0.45 and 0.65% in weeks 5-8 of age, respectively) and sources (DL-methionine (DLM) or DL-methionine hydroxy analogue (MHA))., Results: The HEV added the percentage of CD4 + cells and decreased the percentage of IgM + cells in the blood, spleen and caecal tonsils (CTs) of turkeys. In addition, it increased the percentage of CD4 + CD25 + cells in blood, and interleukin-6 (IL-6) level in plasma. The higher dose of Met led to a significant decrease in the percentages of CD4 + , CD8 + and CD4 + IL-6 + cell subpopulations in the blood of HEV-infected and uninfected turkeys and to an increase in the percentage of IgM + B cells in CTs. Turkeys administered feeds with an increased Met content displayed a decrease in plasma IL-6 levels and an increase in plasma IgA levels., Conclusions: The results of this study indicate that HEV infection impairs the immune function in turkeys. Met content in the feed has a moderate effect on the immune response in HEV-infected turkeys. The source of this amino acid appears not be as important as its dose, because value of the analysed parameters did not differ significantly between turkeys receiving feeds with DLM or MHA. In the uninfected turkeys, the higher by 40% (than recommended by NRC) level of Met in the feeds had a positive effect on humoral immunity parameters.

Continuous outbreaks of highly pathogenic avian influenza (HPAI) viruses in commercial poultry have caused devastating losses to domestic poultry with a raising public health concern. The outbreaks of HPAI viruses have increased worldwide, including the North America. Therefore, vaccination has been considered as an alternative strategy for an efficient control of HPAI viruses. In this study, we aimed to generate Newcastle disease virus (NDV) vectored H7 serotype-specific vaccines by expressing the consensus sequence of the HA protein. Conventional NDV strain LaSota vector and a chimeric NDV vector containing the avian paramyxovirus type-2 F and HN protein were able to express the consensus sequence of HA protein. The protective efficacy of vaccines was evaluated in broiler chickens and in turkeys. One-day-old poults were prime immunized with the chimeric vector expressing the HA protein followed by boost immunization with LaSota vector expressing the HA protein or co-expressing the HA and NA proteins. Our vaccine candidates provided complete protection of broiler chickens from mortality and shedding of H7N8 HPAI challenge virus. Turkeys were better protected by boosting with the LaSota vector co-expressing the HA and NA proteins than the LaSota vector expressing only the HA protein. Our study demonstrated a potential use of heterologous prime and boost vaccination strategy to protect poultry against H7 HPAI viruses., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Immunoglobulins, which are passed vertically from hens to their progeny, are first present in the eggs but with time also in the developing embryos and eventually in the serum of hatching chicks, and have protective function during embryogenesis and in the first few weeks of birds' life, before the immune system becomes fully efficient. Considering the above fact, the aim of this study was to determine total levels of IgM and IgY as well as specific IgY antibody titers against selected pathogens in the serum of breeder turkeys and their progeny, as well as in egg yolks and egg whites. Study results demonstrated that the level of IgY antibodies in the serum of turkey breeder hens reached 22.04 mg/mL on average in the whole egg laying cycle. In addition, the mean transfer percentage of IgY antibodies from turkey layers to their progeny reached approximately 31.4%, but the level of this transfer differed depending on pathogen character and accounted for 33.2%, 51.9%, 45.1%, and 44.3% in the case of antibodies against avian metapneumoviruses, Newcastle disease virus, Ornithobacterium rhinortacheale, and Pasteurella multocida, respectively. Antibody percentage transfer differed also as affected by the stage of the egg production cycle. Study results confirmed the earlier observed dependency concerning the class of antibodies transferred to eggs from laying hens, and while the IgY were mainly detected in the egg yolk extracts, the IgM were found only in egg white extracts; in comparison to IgY, the IgM antibodies were not transferred to the serum of turkey poults. To our best knowledge, this is the first study that describes in detail the phenomenon of maternal antibody transfer in turkeys., (© 2019 Poultry Science Association Inc.)

The aim of this study was to determine the effect of various levels of manganese added to the diet of growing turkeys in the conventional form of MnO or in the form of NP-Mn2O3 nanoparticles on growth performance, absorption, and accumulation of Mn, Zn, and Cu, and antioxidant and immune status. The experiment was conducted on 1080 one-day-old Hybrid Converter turkeys randomly assigned to 6 groups with 10 replications, in a two-factor design with three dosages of manganese - 100, 50, and 10 mg/kg, and two sources-manganese oxide (MnO) and manganese nanoparticles (NP-Mn2O3). Neither reducing the addition of Mn from 100 to 50 or even 10 mg/kg of the diet nor replacing MnO with NP-Mn2O3 had a negative effect on the growth performance of the turkeys. Replacing MnO with NP-Mn2O3 in the turkey diet improved ileal digestibility of Mn and decreased accumulation of Cu in the liver and breast muscle. The study showed that irrespective of the form used, reducing the level of Mn supplementation of the diet from the 100 mg/kg recommended by British United Turkey to 50 or 10 mg/kg decreased its ileal digestibility and increased its accumulation in the liver, breast muscle, and skin. Reducing the addition of Mn to the turkey diet increased intestinal absorption of Zn and reduced accumulation of Zn and Cu in the liver, breast muscle, and skin. It did not increase oxidation processes in the liver or breast muscle of the turkeys. Reducing the addition of Mn to the turkey diet stimulated the immune system, which was manifested by stimulation of B cells to produce immunoglobulin M and by the release of the cytokine IL-6, but did not intensify apoptosis. The results of the study indicate that the recommended manganese supplement in turkey diets can be reduced. The use of manganese nanoparticles in turkey feeding requires further study., (© 2018 Poultry Science Association Inc.)

This study was conducted to identify the effects of 25-OH cholecalciferol supplementation to turkeys on the immune cells parameters, fecal coccidial oocyst shedding, macrophage nitric oxide production, T regulatory cell cytokine production, and production parameters during a coccidial challenge. A total of 200 1-day-old turkey poults were supplemented with 27.5, 55, 82.5, or 110 μg/kg 25-OH cholecalciferol and challenged or not challenged with coccidial oocysts in a 4 × 2 factorial set up of treatments. Birds fed 110 μg/kg of 25-OH cholecalciferol and infected with coccidial oocyst had 41% lower (P < 0.05) fecal oocyst and 53% higher (P < 0.05) macrophage nitric oxide production than the birds fed 27.5 μg/kg of 25-OH cholecalciferol and infected with coccidial oocyst at 5 d post-coccidial infection. Birds fed 82.5 μg/kg 25-OH cholecalciferol and infected with coccidial oocyst had 5-fold higher (P < 0.05) IL-1 mRNA amounts than the birds fed 27.5 μg/kg of 25-OH cholecalciferol and infected with coccidial oocyst. Birds fed 110 μg/kg 25-OH cholecalciferol and infected with coccidial oocyst had 5.3-fold higher (P < 0.05) IL-10 mRNA amounts than the birds fed 27.5 μg/kg of 25-OH cholecalciferol and infected with coccidial oocyst at 5 d post-coccidial infection. CD4+CD25+ cells from birds fed 110 μg of 25-OH cholecalciferol and infected with coccidial oocyst had 12-fold higher (P < 0.05) IL-10 mRNA than that from the birds fed 27.5 μg/kg of 25-OH cholecalciferol and infected with coccidial oocyst. In conclusion, supplementing birds with 101 μg/kg 25-OH cholicalciferol decreases coccidial oocyst shedding in the feces and could be a nutritional strategy to reduce the coccidial infection and spread in turkeys., (© 2018 Poultry Science Association Inc.)

Salmonella vaccine strategies for food-producing animals have typically focused on a specific serovar that either causes production losses due to morbidity/mortality or is an important food safety pathogen for a particular food commodity. The Salmonella enterica serovar Typhimurium BBS 866 vaccine strain was designed to reduce serovar specificity to provide cross-protection against diverse Salmonella serovars, thereby broadening its applicability for multiple animal and poultry species. We reported cross-protection of the BBS 866 vaccine in swine [Vaccine 34:1241-6]. In the current study, we extend the efficacy of the Salmonella vaccine to a poultry commodity by revealing significant reduction of multidrug-resistant Salmonella enterica serovar Heidelberg colonization of the cecum and systemic dissemination to the spleen in BBS 866-vaccinated turkeys. Transcriptional analysis of whole blood from BBS 866-vaccinated turkeys revealed down-regulation of metabolic and immune genes (KCNAB1, ACOD1, GPR17, ADOR2AB, and IL-17RD), suggesting limited leukocyte activation without an overt peripheral inflammatory response to vaccination., (Published by Elsevier Ltd.)

This study evaluated the effects of including 15% of raw or fermented rapeseed cake (RRC and FRC, respectively) in turkey diets on the growth performance, antioxidant and immune status, and intestinal morphology of birds. Rapeseed cake was fermented using the commercial 6-phytase enzyme preparation, and dried. A total of 1,350 day-old female Hybrid Converter turkeys were randomly allocated to 3 dietary treatments with 9 replicates per treatment and 50 birds per replicate. All diets were isonitrogenous and isocaloric, and contained various protein sources. In the control group (C), soybean meal was the main source of dietary protein, and the remaining groups were fed diets containing 15% of RRC or FRC. Fermentation considerably reduced the concentrations of phytate-phosphorus and glucosinolates in rapeseed cake. In comparison with RRC, turkeys receiving FRC achieved higher average final body weight (BW), comparable with that noted in the control group. Both RRC and FRC stimulated the antioxidant system of turkeys, which was reflected in a decrease in the concentrations of lipid hydroperoxides (LOOH) and malondialdehyde (MDA), and an increase in the total antioxidant potential (FRAP) and the concentration of total glutathione (GSH + GSSG) in blood plasma, compared with the control group. Turkeys fed diets with RRC were characterized by the highest blood vitamin C concentrations, the highest activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx), and lower catalase (CAT) activity. The dietary inclusion of rapeseed cake contributed to an increase in villus height and mucosal thickness in the duodenum, and a more beneficial influence was exerted by RRC. It can be concluded that the fermentation of rapeseed cake considerably reduces the concentrations of glucosinolates and phytate-phosphorus, and increases the final BW of turkeys. Diets containing 15% of RRC and FRC do not compromise metabolic parameters or immune function, and exert positive effects on antioxidant status and intestinal histomorphology in turkeys.

The aim of the study was to determine whether the use of Mn nanoparticles would make it possible to reduce the level of this micronutrient added to turkey diets without adversely affecting growth performance, antioxidant and immune status, or apoptosis. The experiment was conducted on 6 groups of turkeys with 10 replications in a two-factor design with 3 dosages of manganese, 100, 50 and 10 mg/kg, and 2 sources, manganese oxide (MnO) and manganese nanoparticles (NP-Mn2O3). The study showed that irrespective of the form of Mn used, reducing the Mn level recommended by British United Turkeys for supplementation of the diet of young turkeys from 100 mg/kg to 10 mg/kg increases the content of this element in the blood with no adverse effect on growth performance or the immune system. The reduction in Mn supplementation in the form of NP-Mn2O3 from 100 to 50 and even to 10 mg/kg of turkey diet has no negative effect on antioxidant defence in young turkeys. A 50% reduction of the recommended Mn level in the form of MnO enhances lipid oxidation processes. Replacing MnO with NP-Mn2O3 in the turkey diet probably can increase apoptosis in young turkeys. On the other hand, irrespective of the form of Mn used, reducing supplementation of the turkey diet with this element from 100 to 50 and even to 10 mg/kg probably can reduce apoptosis., Competing Interests: The authors have declared that no competing interests exist.

Objective: Human Salmonellosis is one of the most frequently reported foodborne zoonoses in the European Union. The most common source of human infections is the consumption of poultry products. Besides management and hygiene practices vaccination of poultry livestock is seen as one way to reduce Salmonella infections in humans. Turkey flocks in Europe are frequently infected with Salmonella and until recently there was no live vaccine for turkeys available. The aim of the present study was to examine the development of humoral antibodies after repeated vaccination with a bivalent live Salmonella vaccine containing attenuated Salmonella Typhimurium and Salmonella Enteritidis strains. Furthermore the colonization of the caecum with the vaccine strains and their spread to liver and spleen as well as the course of their fecal excretion was observed., Results: Antibody production was hardly detectable after the first vaccination but increased after booster vaccinations. Both the Salmonella Enteritidis and the Salmonella Typhimurium vaccine strain were reisolated from caecum contents and organ samples. After booster vaccinations the re-isolation rates were reduced. The shedding of the vaccine strains was most pronounced after the first vaccination.

Histomonosis is a parasitic disease of gallinaceous birds characterized by necrotic lesions in cacum and liver that usually turns fatal in turkeys while it is less severe in chickens. Vaccination using in vitro attenuated Histomonas meleagridis has been experimentally shown to confer protection against histomonosis. The protective mechanisms that underpin the vaccine-induced immune response are not resolved so far. Therefore, the actual study aimed to evaluate the location and quantitative distribution patterns of signature cytokines of type 1 [interferon gamma (IFN-γ)] or type 2 [interleukin (IL)-13] immune responses in vaccinated or infected hosts. An intergroup and interspecies difference in the spatial and temporal distribution patterns of cytokine mRNA positive cells was evident. Quantification of cells showed a significantly decreased percentage of IFN-γ mRNA positive cells at 4 days post-inoculation (DPI) in caeca of turkeys inoculated exclusively with the attenuated or the virulent inocula, compared to control birds. The decrement was followed by a surge of cells expressing mRNA for IFN-γ or IL-13, reaching a peak of increment at 10 DPI. By contrast, turkeys challenged following vaccination showed a slight increment of cecal IFN-γ mRNA positive cells at 4 DPI after which positive cell counts became comparable to control birds. The increase in infected birds was accompanied by an extensive distribution of positively stained cells up to the muscularis layer of cecal tissue whereas the vaccine group maintained an intact mucosal structure. In chickens, the level of changes of positive cells was generally lower compared to turkeys. However, control chickens were found with a higher percentage of IFN-γ mRNA positive cells in cecum compared to their turkey counterparts indicating a higher resistance to histomonosis, similar to the observation in immunized turkeys. In chickens, it could be shown that the changes of cytokine-positive cells were related to variations of mononuclear cells quantified by immunofluorescence. Furthermore, gene expression measured by reverse transcription quantitative real time PCR confirmed variations in organs between the different groups of both bird species. Overall, it can be concluded that a proportionally increased, yet controlled, allocation of IFN-γ mRNA positive cells in caeca hallmarks a protective trait against histomonosis.

A series of studies were undertaken to optimize the propagation of hemorrhagic enteritis virus (HEV) in specific-pathogen-free (SPF) chickens. A total of 562 SPF chickens were orally inoculated with an Australian avirulent HEV isolate of turkey origin at 9, 14, 21, or 28 days of age with 5, 6, 7, or 8 log  10 genomic copies (GC), while 102 chickens served as uninfected controls. No clinical signs were observed in infected chickens. There was an inoculum-dose-dependent increase in the relative spleen and liver weight ( P < 0.01). Relative spleen weight 7 days post-HEV inoculation was up to 85% higher in chickens that were inoculated with 6 to 7 GC compared with controls, with no further increase at higher doses. Relative liver weight increased up to 14% in chickens inoculated with 6 GC, with no further increase. Birds inoculated with a 7 GC dose had a higher frequency of HEV DNA-positive birds (77% to 86%) than birds inoculated with lower doses (33% to 59%; P < 0.01). The most efficient dose for live passage propagation was 7 GC inoculated in 9-to-14-day-old birds, yielding an infection rate of 81%. Livers and spleens from infected birds at all doses were processed to produce a putative vaccine with a final GC recovery in the vaccine material of 8.6 GC/bird. In summary, HEV of turkey origin can be readily propagated in SPF chickens, and conditions to maximize viral retrieval were established.

The aim of this project is to study the clinical signs and lesion of velogenic Newcastle disease (vND) in commercial turkeys, and also to find out if La Sota vaccination offered protection against these signs and lesions. The cockerels were included as positive controls. One hundred and twenty turkey poults and cockerels were divided into eight groups as follows: unvaccinated unchallenged turkeys (UUT), unvaccinated challenged turkeys (UCT), vaccinated unchallenged turkeys (VUT), vaccinated challenged turkeys (VCT), and along the same lines, the cockerel groups were UUC, UCC, VUC and vaccinated challenged cockerels (VCC). Vaccination was at 3 weeks of age while challenge was at 6 weeks of age. The unvaccinated turkeys and cockerels (UCT and UCC) showed different degrees of depression, diarrhoea and later paralysis at challenge. Total mortality was 100% in cockerels within 6 days, but 60% in turkeys. Similar but milder clinical signs were found in the VCC with a total mortality of 13.3%. The VCT showed mild drop in feed and water consumption, and no mortality. All the challenged groups had significant (p < 0.05) loss of weight when compared with their controls. Necropsy showed that while the UCC had severe proventricular haemorrhages, intestinal and caecal tonsil ulcers, the UCT had no digestive tract lesion. There was severe atrophy of the lymphoid organs in all the challenged groups. Histopathological sections of the bursa, spleen and thymus in all the challenged groups with special emphasis on the vaccinated and unvaccinated turkeys with mortalities of 0 and 60%, respectively, had very severe necrosis and depletion of the lymphoid tissue. Virus was isolated from the cloacal swabs. The haemagglutination inhibition antibodies were significantly higher (p < 0.05) in the challenged groups than the unchallenged. The above observations in the intestinal tracts of UCT are of diagnostic significance while the gross and microscopic lesions in the UCT and VCT show that La Sota vaccination may not protect turkeys against the destruction of the lymphoid organs by vND as earlier reported in chickens. This may lead to immunosuppression and production problems in areas where vND is enzootic.

Paraquat (PQ) is used as a herbicide in agriculture and causes oxidative and inflammatory damage to animal tissues. The current study was conducted to investigate the positive effects of dietary propolis (PR), as a potent naturally produced antioxidant, on growth performance and immune function of turkey poults exposed to oxidative stress induced by PQ injection. Native male turkey poults (n = 120, 49-d-old) were randomly assigned into 4 groups: poults received a basal diet with a daily subcutaneous PQ injection of 5 mg/kg BW for 7 consecutive days (PQ group), an experimental diet containing 1 g/kg PR with a daily subcutaneous PQ injection for 7 days (PR+PQ group), or received the experimental PR diet with a daily subcutaneous injection of 0.5 mL sterile saline for 7 days (PR group); while the control poults received a basal diet with a daily subcutaneous saline injection for 7 consecutive days (C group). The productive performance in the PQ group showed a significant (P < 0.05) reduction in the weight gain (WG) and feed intake (FI), and impaired feed conversion ratio (FCR). Propolis supplementation in the PR+PQ group significantly ameliorated the PQ effects on WG and FCR. Turkey poults of the PQ and PR+PQ groups had a significant augmentation in the blood malondialdehyde (MDA), tumor necrosis factor-α (TNFα), and corticosterone levels, and in contrast, a significant reduction in the triiodothyronine (T3), when compared to the C group. While propolis significantly reduced the MDA and corticosterone, and increased the T3 levels in the PR+PQ group compared to the PQ group. Furthermore, the dietary PR supplementation significantly limited the PQ-suppressive effects on cell- and humoral-mediated immunity and lymphocyte proliferation of turkey poults. In addition, propolis supplementation in the PR and PR+PQ groups markedly reversed the PQ-induced DNA fragmentation and heat shock protein 70 (Hsp70) over-expression in blood cells. It can be concluded that PR could improve turkey immunity and performance, particularly under inflammation and oxidative stress induced by PQ exposure., (© 2017 Poultry Science Association Inc.)

Highly pathogenic avian influenza virus (HPAIV) infections are frequently associated with systemic disease and high mortality in domestic poultry, particularly in chickens and turkeys. Clade 2.3.4.4 represents a genetic cluster within the Asian HPAIV H5 Goose/Guangdong lineage that has transmitted through migratory birds and spread throughout the world. In 2014, clade 2.3.4.4 strains entered the U.S. via the Pacific flyway, reassorted with local strains of the North American lineage, and produced novel HPAIV strains of the H5N1, H5N2, and H5N8 subtypes. By 2015, the H5N2 HPAIVs disseminated eastwards within the continental U.S. and Canada and infected commercial poultry, causing the largest animal health outbreak in recent history in the U.S. The outbreak was controlled by traditional mass depopulation methods, but the outbreak was of such magnitude that it led to the consideration of alternative control measures, including vaccination. In this regard, little information is available on the long-term protection of turkeys vaccinated against avian influenza. In this report, a vaccination study was carried out in turkeys using 3 prime-boost approaches with a combination of 2 different vaccines, an alphavirus-based replicon vaccine and an adjuvanted-inactivated reverse genetics vaccine. Vaccine efficacy was assessed at 6 and 16weeks of age following challenge with a prototypic novel clade 2.3.4.4 H5N2 HPAIV. All three vaccines protocols were protective with significantly reduced virus shedding and mortality after challenge at 6weeks of age. In contrast, significant variations were seen in 16-week old turkeys after challenge: priming with the alphavirus-based replicon followed by boost with the adjuvanted-inactivated vaccine conferred the best protection, whereas the alphavirus-based replicon vaccine given twice provided the least protection. Our study highlights the importance of studying not only different vaccine platforms but also vaccination strategies to maximize protection against HPAIV especially with regards to the longevity of vaccine-induced immune response., (Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The hypothesis postulating that the antioxidant and immunological effects of dietary methionine (Met) in young turkeys (1-8 weeks of age) can be differentiated by level and source of Met was investigated in this study. A total of 544 female Hybrid Converter turkeys were divided into four groups and fed diets in which Met content was tailored through supplementation with dl-methionine (dl-Met) or dl-methionine hydroxy analogue (MHA) to levels recommended by NRC (1994) (Groups dl-Met L and MHA L ) and exceeding them by 50% (Groups dl-Met H and MHA H ). Regardless of its source, the increased dietary Met content led to significantly higher body weight gains but had no effect on feed conversion rates. Moreover, an increased Met content lowered lipid peroxide concentrations in breast meat and increased selected indicators of the plasma antioxidant status like uric acid levels, activity of superoxide dismutase (SOD), glutathione (GSH) concentrations, the ferric-reducing ability of plasma (FRAP), increased immunoglobulin A (IgA) plasma levels and decreased interleukin 6 levels. In comparison with dl-Met, MHA decreased the activities of SOD and catalase, and GSH concentrations in plasma. A dosage by source interaction revealed that the lower MHA content was associated with the lowest plasma GSH concentrations, FRAP values and activities of SOD and catalase. The higher dietary MHA level resulted for most parameters similar values, except for a decrease in lipid peroxide concentrations and an increase in plasma IgA levels. It can be concluded that an increased dietary dl-Met and MHA content (about 150% of the recommendations given by NRC 1994) not only increased the growth rate of young turkeys but also improved their antioxidant status. MHA appears to be a less desirable source of dietary Met for young turkeys when the inclusion level of Met matches the current recommendations. Therefore, a further debate is needed to establish the dietary requirements for Met in poultry.

Between December 2014 and June 2015, North America experienced the largest recorded foreign animal disease outbreak with over 47 million poultry dead or euthanized from viral exposure to a clade 2.3.4.4 H5 highly pathogenic avian influenza (HPAI) epizootic. Soon after the epizootic began, the U.S. Department of Agriculture (USDA) began testing the efficacy of different vaccines as a possible future control strategy. The aim of these studies were to evaluate the efficacy three H5 vaccines to aid in control of HPAI in commercial turkeys. Three different vaccine technologies were evaluated for efficacy: 1) inactivated reverse genetic laboratory-generated virus encoding a clade 2.3.4.4 H5 hemagglutinin (HA) gene (rgH5), 2) recombinant turkey herpesvirus encoding a clade 2.2. H5 HA (rHVT-AI), and 3) recombinant replication-deficient alphavirus RNA particle vaccine encoding a clade 2.3.4.4 H5 HA (RP-H5). All vaccines tested significantly (P<0.01) increased survival rates between vaccinated and sham vaccinated groups of poults challenged with A/turkey/Minnesota/12582/2015 clade 2.3.4.4 H5N2 HPAI. The rgH5 vaccine had detectable serum hemagglutination inhibition (HI) antibody against the challenge virus, and significantly reduced the frequency and level of viral shedding from oropharyngeal and cloacal swabs at days 2 and 4 post-challenge. Vaccination with only rHVT-AI or RP-H5 was not 100% protective, and failed to significantly reduce viral shedding post-challenge. A combined prime and boost strategy with the rHVT-AI and RP-H5, or rHVT-AI and rgH5, was 100% protective against lethal H5N2 HPAI challenge. Results of these studies led to USDA conditional approval of commercially available recombinant vaccines for use in turkeys as a control measure for clade 2.3.4.4 H5 HPAI epizootics., (Copyright © 2017. Published by Elsevier B.V.)

The transportation process is one of the most stressful practices in poultry and livestock management. Extensive knowledge is available on the impact of transport on stress and animal welfare; however, little is known on the impact of transport on the physiology of turkey pullets, their welfare and health, and even less on the process of homeostatic recovery in the post-transport new environment. The main focus of this manuscript was to focus on trauma, stress, and recovery following transport of turkey pullets from nurseries to pullet farms. Specifically, we determined the physiological consequences of transport, the temporal restoration of homeostasis and its effects on immune system function. We hypothesized that stress signaling by stress hormones would directly activate circulating turkey blood leukocytes (TBL), thus inducing a pro-inflammatory response directed towards tissue repair and recovery. Extensive blood analyses prior to transit and during the collecting, transit, and post-transit stages revealed extensive stress (elevated heat shock protein 70) and blunt-force trauma (internal bleeding and muscle damage as well as limb fractures). TBL were shown to increase mRNA expression of cortisol and adrenergic receptors during transit, thus indicating a possible direct response to circulating stress hormones. Consequently, TBL were shown to increase mRNA expression of pro-inflammatory cytokines, as well as that of serum inflammatory proteins (lysozyme and transferrin) partaking in reducing oxygen radicals as demonstrated by consumption of these proteins. The flare-up due to transit related stress diminished with time until 10 d post-transit, a time at which most parameters returned to resting levels. Though general and vaccine-specific antibody levels were not altered by transport-related stress, the physical and physiological injury caused during transport may explain the susceptibility of turkey pullets to opportunist pathogens in the immediate post-transit period., (© 2017 Poultry Science Association Inc.)

Avian reoviruses are the causative agent of viral arthritis/tenosynovitis in chickens and turkeys. Clinical signs of disease include swelling of the hock joints accompanied by lesions in the gastrocnemius and digital flexor tendons causing lameness in addition to hydropericardium. The economic impact is significant as it results in poor weight gain, increased feed conversion ratios and condemnations at the processing plant. Vaccination with both live attenuated and inactivated oil emulsion vaccines have been used successfully for decades to control the disease. Current commercial vaccine strains belong to the same serotype and are antigenically and serologically distinct from circulating variant field viruses isolated from clinical cases of tenosynovitis. Since 2012, there has been a dramatic increase in the number of clinical cases of tenosynovitis in commercial poultry and commercial vaccines are unable to provide adequate levels of protection against disease. Producers have elected to use custom inactivated vaccines in the absence of any commercially available homologous vaccines. Identification and selection of field isolates for use in autogenous vaccines can be difficult especially when multiple reoviruses are co-circulating among flocks. In addition, field data suggests that in some cases the custom vaccines are providing adequate protection against disease but as new genetic variants emerge, new vaccines are needed., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Macrophage migration inhibitory factor (MIF) is a soluble protein that inhibits the random migration of macrophages and plays a pivotal immunoregulatory function in innate and adaptive immunity. The aim of this study was to clone the turkey MIF (TkMIF) gene, express the active protein, and characterize its basic function. The full-length TkMIF gene was amplified from total RNA extracted from turkey spleen, followed by cloning into a prokaryotic (pET11a) expression vector. Sequence analysis revealed that TkMIF consists of 115 amino acids with 12.5 kDa molecular weight. Multiple sequence alignment revealed 100%, 65%, 95% and 92% identity with chicken, duck, eagle and zebra finch MIFs, respectively. Recombinant TkMIF (rTkMIF) was expressed in Escherichia coli and purified through HPLC and endotoxin removal. SDS-PAGE analysis revealed an approximately 13.5 kDa of rTkMIF monomer containing T7 tag in soluble form. Western blot analysis showed that anti-chicken MIF (ChMIF) polyclonal antisera detected a monomer form of TkMIF at approximately 13.5 kDa size. Further functional analysis revealed that rTkMIF inhibits migration of both mononuclear cells and splenocytes in a dose-dependent manner, but was abolished by the addition of anti-ChMIF polyclonal antisera. qRT-PCR analysis revealed elevated transcripts of pro-inflammatory cytokines by rTkMIF in LPS-stimulated monocytes. rTkMIF also led to increased levels of IFN-γ and IL-17F transcripts in Con A-activated splenocytes, while IL-10 and IL-13 transcripts were decreased. Overall, the sequences of both the turkey and chicken MIF have high similarity and comparable biological functions with respect to migration inhibitory activities of macrophages and enhancement of pro-inflammatory cytokine expression, suggesting that turkey and chicken MIFs would be biologically cross-reactive., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Salmonellosis is a foodborne zoonosis that is most often acquired by consuming poultry products such as eggs and poultry meat. Amongst other measures the vaccination of food-producing poultry is thought to contribute to a reduction in human salmonellosis. In the European Union (EU) in 2014 the licence of a commercially available Salmonella vaccine for chickens and ducks was extended to turkeys. In the present study, we examined the course of infection with a virulent Salmonella enterica ssp. enterica serovar Enteritidis (SE) strain, a virulent S. enterica ssp. enterica serovar Typhimurium (ST) strain, and the respective live vaccine containing attenuated strains of both serovars in turkey poults. Besides collecting microbiological data and detecting invading Salmonella in the caecal mucosa via immunohistochemistry, we also assessed immune reactions in terms of antibody production, influx of CD4-, CD8α- and CD28-positive cells into the caecal mucosa and the expression of four different immune-related proteins. We found that the attenuated strains were able to invade the caecum, but to a lower degree and for a shorter duration of time compared to virulent strains. Infections with virulent Salmonellae also caused an increase in CD4-, CD8α- and CD28-positive cells in the caecal mucosa and an increased transcription of iNOS, IL-8-like chemokines, and IFN-γ. In poults treated with attenuated bacteria we could not detect any evidence of immune responses. In conclusion, the vaccine showed a lower degree of caecal invasion and induced weaker immune reactions compared to the virulent Salmonella strains in turkeys. The efficiency of the vaccine has to be verified in future studies., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Newly emergent turkey arthritis reoviruses (TARV) were isolated from tendons of lame 15-week-old tom turkeys that occasionally had ruptured leg tendons. Experimentally, these TARVs induced remarkable tenosynovitis in gastrocnemius tendons of turkey poults. The current study aimed to characterize the location and the extent of virus replication as well as the cytokine response induced by TARV during the first two weeks of infection. One-week-old male turkeys were inoculated orally with TARV (O'Neil strain). Copy numbers of viral genes were estimated in intestines, internal organs and tendons at ½, 1, 2, 3, 4, 7, 14 days Post inoculation (dpi). Cytokine profile was measured in intestines, spleen and leg tendons at 0, 4, 7 and 14 dpi. Viral copy number peaked in jejunum, cecum and bursa of Fabricius at 4 dpi. Copy numbers increased dramatically in leg tendons at 7 and 14 dpi while minimal copies were detected in internal organs and blood during the same period. Virus was detected in cloacal swabs at 1-2 dpi, and peaked at 14 dpi indicating enterotropism of the virus and its early shedding in feces. Elevation of IFN-α and IFN-β was observed in intestines at 7 dpi as well as a prominent T helper-1 response (IFN-γ) at 7 and 14 dpi. IFN-γ and IL-6 were elevated in gastrocnemius tendons at 14 dpi. Elevation of antiviral cytokines in intestines occurred at 7dpi when a significant decline of viral replication in intestines was observed. T helper-1 response in intestines and leg tendons was the dominant T-helper response. These results suggest the possible correlation between viral replication and cytokine response in early infection of TARV in turkeys. Our findings provide novel insights which help elucidate viral pathogenesis in turkey tendons infected with TARV.

Wild waterfowl, including mallard ducks, are the natural reservoir of avian influenza A virus and they are resistant to strains that would cause fatal infection in chickens. Here we investigate potential involvement of TRIM proteins in the differential response of ducks and chickens to influenza. We examine a cluster of TRIM genes located on a single scaffold in the duck genome, which is a conserved synteny group with a TRIM cluster located in the extended MHC region in chickens and turkeys. We note a TRIM27-like gene is present in ducks, and absent in chickens and turkeys. Orthologous genes are predicted in many birds and reptiles, suggesting the gene has been lost in chickens and turkeys. Using quantitative real-time PCR (qPCR) we show that TRIM27-L, and the related TRIM27.1, are upregulated 5- and 9-fold at 1 day post-infection with highly pathogenic A/Vietnam/1203/2004. To assess whether TRIM27.1 or TRIM27-L are involved in modulation of antiviral gene expression, we overexpressed them in DF1 chicken cells, and neither show any direct effect on innate immune gene expression. However, when co-transfected with duck RIG-I-N (d2CARD) to constitutively activate the MAVS pathway, TRIM27.1 weakly decreases, while TRIM27-L strongly activates innate immune signaling leading to increased transcription of antiviral genes MX1 and IFN-β. Furthermore, when both are co-expressed, the activation of the MAVS signaling pathway by TRIM27-L over-rides the inhibition by TRIM27.1. Thus, ducks have an activating TRIM27-L to augment MAVS signaling following RIG-I detection, while chickens lack both TRIM27-L and RIG-I itself., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Stress has been shown to affect the immune system of turkeys making them more susceptible to bacterial infections. Five-week-old male and female turkeys were treated with 3 intra-muscular injections of dexamethasone (Dex) at 0, 0.5 and 2.0mg/kg body weight. Twenty-four hours after the third injection birds were bled and white blood cell (WBC) differentials and bacteriostatic activity of monocytes were measured. Dex at both 0.5 and 2.0mg/kg decreased phagocytic activity in females only. Bacteriostatic activity was decreased at both concentrations of Dex at 8 and 16 h post-infection in both sexes and was lower in males as compared to females. Total WBC counts were increased in females at both concentrations of Dex whereas male total WBC counts were unaffected. Both males and females had an increase in the heterophil to lymphocyte ratio. Within the same study, replicate pens of turkeys were challenged with intra-air sac inoculation of 100 cfu of Escherichia coli. Isolation of E. coli was significantly increased by both Dex and E. coli challenge, but there were no differences between sexes. These results suggest that stress can compromise the bacteriostatic activity of turkey monocytes and increase bacterial colonization of blood and tissues, potentially affecting food safety., (Published by Elsevier B.V.)

Background: Avian Metapneumovirus (aMPV) infections are a huge economical issue for the poultry industry worldwide. Although maternal antibodies do not protect turkey poults against turkey rhinotracheitis (TRT), almost no studies have been conducted so far regarding the impact of these antibodies on vaccine induced immunity development against aMPV infection. We conducted four experiments on commercial turkeys aimed at comparing local humoral and cell mediated immune response of maternally delivered anti-aMPV antibody positive (MDA+; Experiment I and II) and negative (MDA-; Experiment III and IV) turkeys following vaccination with an attenuated live aMPV subtype A vaccine at the day of hatch (Experiment I and III) or at two weeks of age (Experiment II and IV)., Results: Regardless of the birds' age, vaccination of MDA- turkeys resulted in strong stimulation of CD8(+) T lymphocytes in the Harderian gland and tracheal mucosa, whereas vaccination of MDA+ birds stimulated mainly CD4(+) T cells in those structures. An increase in the level of anti-aMPV IgY antibodies was noted in the serum (but not in tracheal washings) as early as 7 days after vaccination, but only in birds possessing low levels (MDA+ birds vaccinated at 2 weeks of age) or no maternal anti-aMPV antibodies at the time of vaccination. In MDA+ turkeys vaccinated at hatch, the decrease in serum levels of maternal anti-aMPV antibodies proceeded faster (in comparison to control group), which, together with faster viral clearance, indicates that maternal antibodies can inhibit vaccine virus replication and influence the development of vaccine-induced immunity., Conclusion: This study provides the first documented evidence that the frequency of TRT outbreaks in the field and/or failure of TRT vaccination could be correlated with differences in the immunological status and/or age of vaccinated turkeys.

An experiment was conducted to identify the effect of whole yeast cell product supplementation in turkeys following an experimental inflammatory challenge. A total of 105 one-day-old turkey tom poults were fed basal diets supplemented with 0, 0.1, and 0.2% whole yeast cell product (CitriStim, ADM, Quincy, IL). At 6 wk of age and 16 wk of age, turkeys were injected with lipopolysaccharide (LPS) at 0 or 0.25 mg/kg of BW in a 3 × 2 factorial arrangement. BW gain (P = 0.31) and feed conversion ratio (P = 0.53; 3.13, 2.94, and 2.98 for the 0, 0.10, and 0.20% CitriStim treatments, respectively) at 15 wk of age were not significantly affected by the treatment diets. Yeast cell wall product supplementation had no effect on growth in control-injected turkeys but decreased growth in LPS-injected turkeys (yeast × LPS, P < 0.05). Splenic macrophages from birds fed whole yeast cell product and injected with LPS produced higher (P < 0.01) nitric oxide than the control group injected with LPS at both 6 and 16 wk of age. At 6 and 16 wk of age, birds injected with LPS (P < 0.01; P < 0.01) and supplemented with whole yeast cell product (P = 0.05; P = 0.10) showed increased IL-1 mRNA amounts in cecal tonsils. In birds not injected with LPS, whole yeast cell supplementation increased regulatory T cell percentage and IL-10 mRNA amounts, whereas in birds injected with LPS, whole yeast cell supplementation decreased IL-10 mRNA amounts at both 6 (P < 0.01) and 16 wk (P = 0.01) of age in cecal tonsils. Whole yeast cell product supplementation increased Lactobacillus (P < 0.01 and P = 0.01) and Bifidobacteria (P < 0.01 and P = 0.01) population at 6 and 16 wk of age. In conclusion, the effect of feeding whole yeast cell product on turkeys was dependent on the inflammatory status of the bird., (©2014 Poultry Science Association Inc.)

Clostridia represents a group of anaerobic spore-forming bacteria ubiquitous in the poultry environment. They are widely distributed in soil and survive for many years as highly resistant, inactive spores. They enter the body through wounds and contaminated feed as active bacteria or spores. Multiplication of clostridial bacteria occurs only in the absence of oxygen or in environments with very low concentrations of oxygen. During active multiplication, the clostridial organisms produce several toxins that are responsible for most of the clinical signs seen in clostridial diseases. Immunosuppression is a problem for the poultry industry. In modern, intensive poultry-rearing conditions, stress due to high population densities pose a considerable challenge for the immune system, and infectious agents can exploit this situation to cause disease. Immunosuppression may predispose turkeys to clostridial infection, resulting in clostridial dermatitis and mortality. The purpose of this study was to determine whether immunosuppression predisposes turkeys to clostridial infection and causes clostridial dermatitis. We immunosuppressed 10-wk-old turkey poults with dexamethasone. The birds immunosuppressed and not immunosuppressed were then challenged with Clostridium perfringens, Clostridium septicum, or both and examined for the development of clostridial dermatitis. The dexamethasone-treated birds were found to be more susceptible to C. peifingens/C. septicum challenge and developed clostridial dermatitis than the no-dexamethasone-treated birds through the subcutaneous route. However, oral inoculation of the same agents did not cause any dermatitis lesions in either of the groups.

Toxoplasma gondii is a parasite which can be transmitted to humans via the consumption of contaminated meat products derived from different animal species, e.g., poultry. In Europe, the consumption rate of poultry meat is high and may pose a risk for humans. However, little is known about the prevalence and immune response against T. gondii in these animals. Based on these circumstances, we experimentally infected 18 turkeys and 16 chickens with the parasite. Turkeys were infected either with tachyzoites on different routes or with various amounts of oocysts. In contrast, chickens were only infected with different doses of oocysts. The immunoglobulin (Ig) Y humoral immune responses of these animals were investigated in a lineblot assay against the recombinant T. gondii antigens rGRA1, rGRA6, rGRA9, rSAG1, and rSUB1. By using the recombinant antigens rGRA6, rGRA9, and rSUB1 in the lineblot assay, we found a correlation between the humoral immune response and the parasite stage in turkeys. Thereby, an infection with oocysts induced a stronger, permanent long-lasting antibody response compared to tachyzoite-infected animals. Only a minor relation between the oocyst infection dose and the manifestation of the immune response in chickens was found 7 days post infection (dpi) by using rGRA1 and rGRA9. However, an inconstant detection of antigen-specific IgY antibodies in the lineblot assay seems not to be a sufficient method for the identification of a Toxoplasma infection in chickens. In contrast, the detection of anti-rGRA6, anti-rGRA9, and anti-rSUB1 IgY antibodies showed potential for the identification of an infection in turkeys.

The aim of this research work was to indicate the influence of Citrosept preparation and Scutellaria baicalensis root extract, administered per os to growing turkey hens in 3 different dosages, on the content of selected mineral elements in blood plasma of slaughter turkey hens. An attempt was also made to specify the most effective dosage of the applied preparations with the highest efficiency as regards increased levels of examined macro- and microelements in the birds' blood. The research experiment was conducted on 315 turkey hens randomly divided into seven groups, each consisting of 45 turkey hens. Group K constituted the control group without experimental additions of the above-mentioned preparations. When it comes to turkey hens which belonged to groups II-IV, Citrosept preparation was instilled to water in the following dosages: Group II - 0.011 ml/kg of bm; Group III - 0.021 ml/kg of bm; Group IV - 0.042 ml/kg bm. For birds which belonged to groups V-VII preparation, which was Scutellaria baicalensis root extract, was instilled to water in the following dosages: Group V - 0.009 ml/kg of bm; Group VI - 0.018 ml/kg of bm, Group VII - 0.036 ml/kg bm. In the examined plant extracts and blood plasma of the birds the levels of Na, K, Ca, Mg, Cu, Zn, and Fe were identified. The use of examined extracts influenced the changes in the levels of all tested elements in slaughter turkey hens' blood plasma. An upward tendency was recorded which regarded the level of calcium and magnesium, and a downward tendency of sodium, potassium, copper, zinc, and iron in relation to the results achieved in the control group.

Introduction and Objective: The objective of this study was to determine the effect of per os administration of 3 various dosages of a Citrosept preparation (a grapefruit extract)to growing turkey hens on changes in their selected haematological and immunological blood indices. An attempt was also undertaken to select the most efficient dose of the preparation with respect to the mentioned indices in turkey hens., Materials and Methods: The experiment was conducted on 180 turkey hens allocated at random to 4 groups, 45 birds in each group. Samples of their full blood were analyzed for haematological indices, such as red blood cell count (RBS), haemoglobin content (Hb), haematocrit value (Ht), and white blood cell count (WBC). Samples of blood plasma were assayed to determine the activity of lysozyme (chamber-diffusive method) and heterophils capability to reduce nitro blue tetrazolium (stimulated and spontaneous NBT test). Phagocytic activity of leucocytes against Staphylococcus aureus 209P strain was assessed and expressed as the percentage of phagocytic cells (% PC) and phagocytic index (PI)., Results: The administration of the grapefruit extract to turkey hens with drinking water caused a significant increase in haemoglobin content in blood, as well as an increase in non-specific humoral immunity marker (activity of lysozyme) and non-specific cellular immunity marker (percentage of phagocytic cells; P ≤ 0.05)., Conclusions: The results obtained enabled the positive evaluation of the advisability of applying the Citrosept preparation in the feeding of turkey hens at the age of 6-9 weeks. Among the doses examined, the most efficient with respect to the stimulation of the non-specific humoral and cellular immunity was the dose of 0.021 ml/kg of body weight.

The objective of this study was to determine the effect of whole wheat feeding on selected parameters of humoral and cell-mediated immunity in growing turkeys. A total of 210 one-day-old heavy-type Hybrid Converter male turkeys were randomly divided into three different dietary treatment groups, each consisting of 7 replicate pens of 10 birds per pen. Until 4 wk of age, all birds were fed a commercial diet formulated to meet nutrient requirements. From 5 to 12 wk of age, diets were composed of wheat (ground-pelleted or whole grain) and protein-fat-mineral-vitamin concentrate. The total wheat concentration in diets was 500 or 600 g/kg in the feeding periods of 5-8 and 9-12 wk of birds' age, respectively. Whole grain wheat had a 0, 50 or 100% share of the total wheat amount in the daily ration in treatment groups W0, W50 or W100, respectively. Commercial vaccines against ND (Newcastle disease) and TRT (Turkey rhinotracheitis) were administered to turkeys via the drinking water on days 20 and 30, respectively. Over the entire experiment, a significant linear decrease was observed in body weight gains (BWG) with increasing dietary levels of whole grain wheat. As a result the BWG of control turkeys (W0) were significantly higher than the BWG of group W100 birds (P = 0.002). A significant linear increase in feed conversion ratio (FCR) was observed with increasing dietary levels of whole grain wheat (P < 0.001). The levels of antibodies against TRT and ND viruses after immunization were significantly higher in both the W50 and W100 group, in comparison to group W0 (P = 0.006 and P = 0.001, respectively). Turkeys from group W50, in comparison to those from groups W0 and W100, had a significantly higher percentage of CD4+ T cell subpopulation within the lymphocytes isolated from blood and ileal mucosa, as well as CD4+ CD8+ and CD8+ T cell subpopulations within the blood immunocompetent cells (P = 0.022, P = 0.029, P = 0.009 and P = 0.011, respectively). In the cecal tonsils, the percentage of CD8+ T cell subpopulation was significantly lower in group W50 than in groups W0 and W100 (P = 0.014). The results of our study indicate that diluting diets with whole grain wheat stimulates the non-specific cell-mediated defense mechanisms of the gastrointestinal immune system in turkeys, thus positively affecting humoral response after vaccination.

The avian MHC-associated gene set includes orthologs to genes found throughout the human major histocompatibility complex (MHC), including some loci of the evolutionarily conserved class III region. In the turkey and other Galliformes, genes linked to the MHC have been identified because they are closely associated with class I or class II genes. This study was designed to evaluate additional class III genes for linkage to the avian MHC to further determine conservation of these loci in birds. BLAST searches were used to locate sequences in the turkey genome with similarity to genes shared between the MHC of Xenopus and humans. Primers were designed to target 25 genes, and putative orthologs were amplified by PCR and sequenced. Sequence polymorphisms were identified for 15 genes in turkey reference mapping families, and 8 genes showed significant genetic linkage to the turkey MHC-B locus. These new genetic markers and linkage relationships broaden our understanding of the composition of the avian MHC and expand the gene content for the turkey MHC-B., (© 2014 S. Karger AG, Basel.)

The objective of this study was to determine the effect of different levels of dietary methionine on selected immune parameters of young turkeys. A total of 357 one-day-old female Hybrid Converter turkeys were randomly divided into three groups with low, medium and high level of dietary me- thionine (LM, MM, HM) of seven replicates each. Methionine was added to the basal diet (LM) at 0.16% (MM) and 0.32% (HM). At 17 days of age, seven birds per group were vaccinated against Ornithobacterium rhinotraheale (ORT) infection, with ORNITIN (ABIC) vaccine. At 28 days of age, blood was sampled and the birds were euthanized. The serum concentrations and activity of selected biochemical parameters, total IgY and IgM, and vaccine-induced antibody titers (IgY) against ORT were determined. The percentages of CD4+, CD8+, CD4+/CD8+ T cell subpopulations and IgM+ B cell subpopulation were determined in blood and organs by flow cytometry. Different supplementary levels of methionine had no significant effect on vaccine-induced anti- body titers against ORT or total serum IgM and IgY levels, as well as on the percentages of periph- eral blood T and B cell subsets. Increasing dietary methionine rates decreased the percentage of CD4+ T cell subpopulation, however it has increased the percentage of IgM+ B cell subpopulation in the spleen. Vaccination against ORT resulted in a significant decrease in the percentage of CD4+ T cell subset and an increase in the percentage of CD8+ T cell subset in the spleen. It could be concluded that MM turkeys have developed the most desirable values of immune parameters.

ONRAB(®) is a recombinant human adenovirus type 5 (HAd5) with the rabies glycoprotein gene incorporated into its genome. ONRAB(®) has been used in Canada as an oral rabies vaccine in target wildlife species such as: red fox (Vulpes vulpes), raccoon (Procyon lotor), and striped skunk (Mepthis mephitis). We evaluated the safety of ONRAB(®) in non-target wildlife species likely to contact the vaccine baits during oral rabies vaccine campaigns in the United States. We investigated the effects of oral inoculation of high titer ONRAB(®), approximately ten times the dose given to target species, in wood rats (Neotoma spp.), eastern cottontail rabbits (Sylvilagus floridanus), Virginia opossums (Didelphis virginiana), eastern wild turkeys (Meleagris gallopavo silvestri), and fox squirrels (Sciurus niger). We performed real-time polymerase chain reaction (PCR) on fecal swabs, oral swabs, and tissues, including lung, liver, kidney, small intestine, large intestine, and when appropriate nasal turbinates, to detect ONRAB(®) DNA from inoculated animals. By seven days post-inoculation, turkeys, opossums, and cottontails had all stopped shedding ONRAB(®) DNA. One wood rat and one fox squirrel still had detectable levels of ONRAB(®) DNA in fecal swabs 14 days post-inoculation. Real-time PCR analysis of the tissues revealed some ONRAB(®) DNA persisting in certain tissues; however, there were no significant gross or histologic lesions associated with ONRAB(®) in any of the species studied. Our results suggest that many non-target species are not likely to be impacted by the distribution of ONRAB(®) as part of oral rabies vaccination programs in the United States., (Published by Elsevier Ltd.)

The present study was undertaken to determine immune response and protection efficacy of a spike (S) protein fragment containing neutralizing epitopes (4F/4R) of turkey coronavirus (TCoV) by priming with DNA vaccine and boosting with the recombinant protein from the corresponding DNA vaccine gene segment. Turkeys were vaccinated by priming with either one dose (G1-750DP) or two doses (G3-750DDP) of 750μg DNA vaccine expressing 4F/4R S fragment and boosting with one dose of 200μg 4F/4R S fragment. One dose of 100μg DNA vaccine mixed with polyethyleneimine (PEI) and sodium hyaluronate (HA) followed by one dose of 750μg DNA vaccine and one dose of 200μg 4F/4R S fragment were given to the turkeys in group G2-100DPH. After infectious challenge by TCoV, clinical signs and TCoV detected by immunofluorescence antibody (IFA) assay were observed in less number of turkeys in vaccination groups than that in challenge control groups. TCoV viral RNA loads measured by quantitative real-time reverse transcription-PCR were lower in vaccinated turkeys than those in challenge control turkeys. The turkeys in G3-750DDP produced the highest level of TCoV S protein-specific antibody and virus neutralization (VN) titer. Comparing to the turkeys in G1-750DP, significantly less TCoV were detected by IFA in the turkeys in G2-100DPH receiving an extra dose of 100μg DNA mixed with PEI and HA. The results indicated that DNA-prime protein-boost DNA vaccination regimen targeting TCoV S fragment encompassing neutralizing epitopes induced humoral immune response and partially protected turkeys against infectious challenge by TCoV., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The cDNAs of two turkey cytokines, interleukin (IL)-10 and IL-13, were cloned using oligonucleotide primers designed from their chicken orthologues. The coding regions of the chicken and turkey genes are highly conserved, with IL-10 and IL-13 exhibiting 94.1% and 90% nucleotide and 92% and 79.9% amino acid identity respectively. Both showed consistent mRNA expression in turkey lymphoid and gut tissues. Expression in non-lymphoid tissues was more variable but generally highest in the skin and trachea. Recombinant turkey IL-10 was expressed and bioactivity demonstrated by inhibition of IFN-γ synthesis from activated splenocytes. Chicken and turkey IL-10 cross-reacted in functional assays., (Copyright © 2012 Elsevier B.V. All rights reserved.)

To date, most jawed vertebrate species encode more than one immunoglobulin light (IgL) chain isotypes. It has been shown that several bird species (chickens, white Pekin or domestic duck, and zebra finches) exclusively express lambda isotype. We analyze here the genomic organization of another bird species turkey IgL genes based on the recently released genome data. The turkey IgL locus located on chromosome 17 spans approximately 75.2kb and contains a single functional V(λ) gene, twenty V(λ) pseudogenes, and a single functional J(λ)-C(λ) block. These data suggest that the genomic organization of bird IgL chain genes seems to be conserved. Ten cDNA clones from turkey Igλ chain containing almost full-length V(λ), J(λ) and C(λ) segments were acquired. The comparison of V(λ) cDNA sequences to all the germline V(λ) segments suggests that turkey species may be generating IgL chain diversity by gene conversion and somatic hypermutation like the chicken. This study provides insights into the immunoglobulin light chain genes in another bird species., (Copyright © 2012. Published by Elsevier B.V.)

The MHC of the turkey (Meleagris gallopavo) is divided into two genetically unlinked regions; the MHC-B and MHC-Y. Although previous studies found the turkey MHC-B to be highly similar to that of the chicken, little is known of the gene content and extent of the MHC-Y. This study describes two partially overlapping large-insert BAC clones that genetically and physically map to the turkey MHC chromosome (MGA18) but to a region that assorts independently of MHC-B. Within the sequence assembly, 14 genes were predicted including new class I- and class IIB-like loci. Additional unassembled sequences corresponded to multiple copies of the ribosomal RNA repeat unit (18S-5.8S-28S). Thus, this newly identified MHC region appears to represent a physical boundary of the turkey MHC-Y. High-resolution multi-color fluorescence in situ hybridization studies confirm rearrangement of MGA18 relative to the orthologous chicken chromosome (GGA16) in regard to chromosome architecture, but not gene order. The difference in centromere position between the species is indicative of multiple chromosome rearrangements or alternate events such as neocentromere formation/centromere inactivation in the evolution of the MHC chromosome. Comparative sequencing of commercial turkeys (six amplicons totaling 7.6 kb) identified 68 single nucleotide variants defining nine MHC-Y haplotypes. Sequences of the new class I- and class IIB-like genes are most similar to MHC-Y genes in the chicken. All three loci are expressed in the spleen. Differential transcription of the MHC-Y class IIB-like loci was evident as one class IIB-like locus was only expressed in some individuals.

The use of protective, probiotic cultures in poultry farming may serve as a useful strategy to improve food product safety from the beginning of the food chain and thus to protect consumer health. The objective of this study was to investigate the effect of the probiotic strain Bifidobacterium longum PCB133 on innate and adaptive immune responses in turkeys beginning at 2 wk of age, under farming conditions. The vaccination efficiency against Newcastle disease virus served as the primary endpoint. At 2 wk of age, male turkeys (British United Turkey Big 6 strain) were randomly assigned to the control (n = 25) or probiotic group (n = 25). Turkeys in the probiotic group received the probiotic B. longum PCB133 (at least 3 × 10(7) cfu/d) incorporated into the daily feed ration for 5 wk, until slaughter at 7 wk of age. At the beginning of the probiotic intervention, birds in both groups were vaccinated against Newcastle disease. Birds were weighed weekly throughout the intervention period, and finally blood sera and heparinized blood were collected for immune function tests (lymphocyte proliferation, phagocytosis, respiratory burst), and for the determination of Newcastle disease virus antibody titers. No effects on BW gain and on the proliferation of blood lymphocytes were elicited by the 5-wk intervention with the probiotic. Concerning the primary endpoint of the study (i.e., specific antibody production as a response to vaccination against Newcastle disease), no adjuvant effect of the probiotic could be determined. In addition, innate immune functions tested were not significantly affected. In conclusion, first scientific evidence on the application of the probiotic strain B. longum PCB133 in turkeys beginning at 2 wk of age does not support an improvement in live performance, humoral immunity, or innate immunity.