Probiotic supplementation containing Bacillus velezensis enhances expression of immune regulatory genes against pigeon circovirus in pigeons (Columba livia).

AIMS: In this study, we aimed to isolate and evaluate the efficacy of Bacillus velezensis as a probiotic and to assess its activity towards pigeons infected with pigeon circovirus (PiCV). METHODS AND RESULTS: Bacillus velezensis, isolated from pigeon faeces, was orally administered to pigeons for 60 days. After pigeons were challenged with PiCV, the PiCV viral load and expression of indicator genes for innate immunity were detected in spleen tissue and faeces of pigeons. Bacillus velezensis significantly reduced the PiCV viral load in the faeces and spleen of pigeons 5 days post-challenge (dpc). The mRNA expression levels of treated pigeons showed that interferon-gamma (IFN-γ), myxovirus resistance 1 (Mx1), and signal transducers and activators of transcription 1 (STAT1) genes were upregulated, whereas no expression of interleukin-4 (IL-4) was detected. Moreover, toll-like receptor 2 (TLR2) and 4 (TLR4) were significantly upregulated in probiotic-treated pigeons (P < 0·05). CONCLUSIONS: This is the first report showing that probiotic supplementation can effectively enhance the T-helper type 1 immune response and decrease the PiCV viral loads in pigeons. SIGNIFICANCE AND IMPACT OF THE STUDY: This study proposes that the administration of a probiotic strain, B. velezensis, to pigeons can protect against PiCV infection.

The impact of Aloe vera and licorice extracts on selected mechanisms of humoral and cell-mediated immunity in pigeons experimentally infected with PPMV-1.

BACKGROUND: The aim of the study was to evaluate the impact of herbal extracts on selected immunity mechanisms in clinically healthy pigeons and pigeons inoculated with the pigeon paramyxovirus type 1 (PPMV-1). For the first 7 days post-inoculation (dpi), an aqueous solution of Aloe vera or licorice extract was administered daily at 300 or 500 mg/kg body weight (BW). The birds were euthanized at 4, 7 and 14 dpi, and spleen samples were collected during necropsy. Mononuclear cells were isolated from spleen samples and divided into two parts: one part was used to determine the percentage of IgM+ B cells in a flow cytometric analysis, and the other was used to evaluate the expression of genes encoding IFN-γ and surface receptors on CD3+, CD4+ and CD8+ T cells. RESULTS: The expression of the IFN-γ gene increased in all birds inoculated with PPMV-1 and receiving both herbal extracts. The expression of the CD3 gene was lowest at 14 dpi in healthy birds and at 7 dpi in inoculated pigeons. The expression of the CD4 gene was higher in uninoculated pigeons receiving both herbal extracts than in the control group throughout nearly the entire experiment with a peak at 7 dpi. A reverse trend was observed in pigeons inoculated with PPMV-1 and receiving both herbal extracts. In uninoculated birds, increased expression of the CD8 gene was noted in the pigeons receiving a lower dose of the Aloe vera extract and both doses of licorice extracts. No significant differences in the expression of this gene were found between inoculated pigeons receiving both herbal extracts. The percentage of IgM+ B cells did not differ between any of the evaluated groups. CONCLUSIONS: This results indicate that Aloe vera and licorice extracts have immunomodulatory properties and can be used successfully to prevent viral diseases, enhance immunity and as supplementary treatment for viral diseases in pigeons.

Effects of zinc-methionine on growth performance, intestinal flora and immune function in pigeon squabs.

1. Different concentrations of zinc-methionine (Zn-Met) were given to pigeon squabs, and the resulting effects on growth, immune functions and intestinal microflora were investigated from hatching to 28 d of age. A total of 180 artificially hatched pigeon squabs were randomly allotted to each of three treatments with three replicates of 20 squabs. The three treatments given were either one ml (2 mg/ml) Zn-Met, one ml (10 mg/ml) Zn-Met or one ml 0.9% NaCl solution. 2. The results showed that Zn-Met improved the growth performance of squabs. The average daily and average weekly weight gain was significantly greater in squabs treated with Zn-Met than in the control group. 3. The group given 2 and 10 mg supplemental Zn-Met had heavier thymus, spleen and bursa of Fabricius than the control group at d 28. 4. Maternal antibody titres against Newcastle disease haemagglutination inhibition and alpha-naphthyl acetate esterase were significantly higher in squabs treated with supplemental 2 and 10 mg Zn-Met compared to the control group at d 14 and d 28. 5. Additionally, the squabs given supplemental 2 mg Zn-Met exhibited significantly higher Bacillaceae, Lactobacillus, Enterococcus and Bifidobacterium populations at d 14 and d 28, but lower Escherichia coli populations at d 28 compared to the control group. On the contrary, Lactobacillus, Enterococcus and Bifidobacterium populations were significantly decreased with 10 mg Zn-Met at d 28. 6. This study indicates that supplementation with Zn-Met has a positive effect on growth performance, immune function and regulation of intestinal flora in pigeons. An inclusion level of 2 mg seems to be better than 10 mg Zn-Met per day per bird.

Effects of immune supplementation and immune challenge on oxidative status and physiology in a model bird: implications for ecologists.

One route to gain insight into the causes and consequences of ecological differentiation is to understand the underlying physiological mechanisms. We explored the relationships between immunological and oxidative status and investigated how birds cope physiologically with the effects of immune-derived oxidative damage. We successively implemented two experimental manipulations to alter physiological status in a model bird species: the homing pigeon (Columba livia). The first manipulation, an immune supplementation, was achieved by oral administration of lysozyme, a naturally occurring and non-specific antimicrobial enzyme. The second manipulation, an immune challenge, took the form of an injection with lipopolysaccharide, a bacterial endotoxin. Between groups of lysozyme-treated and control birds, we compared lipopolysaccharide-induced changes in reactive oxygen metabolites, total antioxidant capacity, haptoglobin, oxygen consumption, body mass and cloacal temperature. Lysozyme supplementation intensified the lipopolysaccharide-induced inflammatory response and generated short-term oxidative and metabolic costs. We identified significant interactions between immune supplementation and immune challenge in terms of reactive oxygen metabolites, haptoglobin and oxygen consumption. Our study provides alternative interpretations of differences in oxidative and immunological indices and demonstrates that these indices can also fluctuate and interact across very short time scales, reflecting something akin to current 'health status' or 'physiological condition'. These ephemeral effects highlight the need to broadly consider current physiological condition when drawing conclusions that relate physiology to ecology and evolution.

Immunomodulating effects of black seed and oxytetracycline in pigeons.

Chronic administration of oxytetracycline (OXT) (incorporated at a level of 0.05 g per kg of feed for 50 days) to pigeons, significantly decreased total leukocyte and lymphocyte counts, increased heterophil:lymphocyte ratio and lysosomal enzyme activity, and decreased reticuloendothelial system function compared with controls. Coadministration of black seed (BS) at a level of 2.5% with OXT completely blocked the effects elicited by OXT and produced immunostimulant effects in pigeons. The addition of BS to feed of pigeons could act as an immunoprotective agent when chronic administration of antibiotics are considered.

Enhanced specific antibody response to bovine serum albumin in pigeons due to L-carnitine supplementation.

1. Thirty adult female pigeons (Columba livia domestica) were randomly divided into 3 equal groups; the 1st and 2nd groups were immunised with bovine serum albumin (BSA) at 0 and 20 d, the 2nd group also received 1 g L-carnitine per litre of drinking water from -5 to 25 d post-immunisation (dpi) and the 3rd group, a control group, received neither treatment. 2. Body weights and serum samples were taken at 0, 5, 10, 15, 20, 25, 30 and 35 dpi. 3. Both BSA-specific IgG and IgM responses were enhanced by about 10% by L-carnitine supplementation. 4. L-carnitine supplemented pigeons showed a higher water consumption. Body weight loss during the onset of the immune response showed a slight tendency to be counteracted by L-carnitine supplementation. 5. The impact of L-carnitine on resistance and resilience to an immunological challenge is discussed.

The extracellular domain of the zeta-chain is essential for TCR function.

The zeta-chain homodimer is a key component in the TCR complex and exerts its function through its cytoplasmic immunoreceptor-tyrosine activation motif (1). The zeta-chain extracellular (EC) domain is highly conserved; however, its functional and structural contributions to the TCR signaling have not been elucidated. We show that the EC domain of the zeta homodimer is essential for TCR surface expression. To gain a more detailed structural and functional information about the zeta-chain EC domain, we applied a cysteine scanning mutagenesis to conserved amino acids of the short domain. The results showed that the interchain disulfide bridge can be displaced by seven or eight amino acids along the EC domain. The TCR signaling efficacy was dramatically reduced during peptide/MHC engagement in the zeta mutants containing the displaced disulfide bond. These signaling defective zeta mutants produced an unconventional early tyrosine phosphorylation pattern. While the tyrosine phosphorylated forms of zeta (p21 and p23) could be observed during Ag stimulation, downstream signaling events such as the generation of phospho-p36, higher m.w. forms of phospho-zeta, and phospho-zeta/ZAP-70 complexes were impaired. Together these results suggest an important function of the phylogenetically conserved zeta-EC domain.

Hypersensitivity pneumonitis in workers exposed to esparto grass (Stipa tenacissima) fibers.

Esparto grass (Stipa tenacissima), which is commonly found in the Mediterranean countries, has a wide variety of uses. Five stucco makers who had cough, dyspnea, malaise, and fever after exposure to esparto fiber used in their jobs showed a significant decrease in symptoms when they were away from work. Precipitating antibodies against an esparto extract were found in the sera of all patients. Specific IgG antibodies against the esparto extract were also demonstrated in all patient sera, as were IgG antibodies to Aspergillus fumigatus and thermophilic microorganisms (Micropolyspora faeni and Thermoactinomyces vulgaris) by means of an ELISA method. Esparto activity was inhibited in different ranges by the above antigens by inhibition ELISA. Only A. fumigatus could be identified after microbiologic evaluation of the esparto fiber samples. After inhalation challenge tests were performed with esparto extracts, all patients showed significant decreases in forced vital capacity, transfer lung CO, and PaO2 blood gas from baseline values. Fever, chills, malaise, dry cough, tachycardia, tachypnea, and rales on chest auscultation were also observed in all patients. Findings from bronchoalveolar lavage were suggestive of allergic alveolitis. Transbronchial biopsy specimens showed interstitial alveolitis with lymphocyte-macrophage infiltrate and granuloma. Unexposed control subjects did not exhibit reactivity to any of the tests listed above. The dust derived from esparto fibers can cause hypersensitivity pneumonitis in exposed subjects. Organisms such as A. fumigatus and thermophilic actinomyces could be the causative antigens. "Stipatosis" might be an appropriate name for this disorder.

Outer membrane of avian myeloblastosis virus.

Guinea pigs immunized intracerebrally with avian myeloblastosis virus (AMV) produced antiserum which reacted with intact virus particles in complement fixation. The antigen in question appeared to be located on the surface of the virion and could be distinguished from the type-specific virus envelope and the group-specific internal antigens of chicken leukosis-sarcoma viruses (ChiLSV). The material could be isolated by sequential treatments of AMV with bromelin, Tween 20, and freeze-thawing, and could be purified by differential centrifugation. Electron microscopy analysis indicated the presence of a component resembling the outer membrane of the particle. The antigenic determinant was designated virus membrane antigen (Vm). Further analyses revealed the presence of protein, lipid, and carbohydrate in a material having a molecular weight of about 6,000 as determined by sodium dodecyl sulfate gel electrophoresis. Serological studies suggested that the outer membranes of AMV and other ChiLSV are represented mainly by host cellular material.