Gastrointestinal response to the early administration of antimicrobial agents in growing turkeys infected with Escherichia coli.

This study investigated the effects of the early administration of enrofloxacin (E) or doxycycline (D) for the first 5 consecutive days of life, or the continuous administration of the coccidiostat monensin (M) throughout the rearing period on gastrointestinal function in turkeys infected with avian pathogenic Escherichia coli (APEC) in an early or later stage of rearing. Experiment 1 lasted 21 d, and turkeys in groups E, D, and M were infected with APEC on d 15. Experiment 2 lasted 56 d, and it had a factorial arrangement of treatments where birds in groups E, D, and M were infected with APEC on d 15 or d 50. In both experiments, control groups (C) consisted of infected and uninfected birds without antibiotic or coccidiostat administration. On d 21 (Experiment 1) and d 56 (Experiment 2), 8 birds from each subgroup were killed, and the ileal and cecal digesta were sampled to analyze the activity of bacterial enzymes and the concentrations of short-chain fatty acids (SCFA). The experimental treatments did not affect the final body weight or body weight gain of birds. Both experiments demonstrated that APEC contributed to an increase in ammonia levels of the cecal digesta (means from 2 experiments: 0.311 vs. 0.225 mg/g in uninfected birds) and ileal pH (6.79 vs. 6.00) and viscosity (2.43 vs. 1.83 mPa⋅s). Moreover, the E. coli challenge enhanced the extracellular activity of several cecal bacterial enzymes, especially in older turkeys infected with APEC in a later stage of life. The continuous administration of monensin throughout the rearing period resulted in a weaker gastrointestinal response in older birds, compared with the other 2 antibiotics administered for the first 5 d of life. The results of the study are inconclusive as both desirable and undesirable effects of preventive early short-term antibiotic therapy were observed in turkeys, including normalization of ileal viscosity and cecal ammonia concentration (positive effect), and disruption in cecal SCFA production (negative effect).

The impact of full-fat Hermetia illucens larvae meal on the health and immune system function of broiler chickens.

Introduction: Alternative protein sources have recently been attracting growing interest as potential components of livestock nutrition. This study evaluated the effect on broiler health of replacing the soybean protein component of poultry feed with processed insect protein from farmed Hermetia illucens (HI) larvae. Material and Methods: A total of 384 male broiler chicks were divided into four diet groups (eight pens/treatment and 12 birds/pen) and reared to the 42nd day of life (dol). Each treatment group received a starter diet until the 14th dol, then a grower diet until the 35th and finally a finisher diet until the 42nd. The soybean meal in standard diets was replaced with full-fat HI larvae meal in the following amounts: 0% for the control group HI-0, 50% for group HI-50, 75% for group HI-75, and 100% for group HI-100. At 1 dol, chicks were vaccinated against Marek's disease, coccidiosis, Newcastle disease and infectious bronchitis and at 7 dol against avian metapneumovirus infections using live-attenuated vaccines. Blood and spleen samples were collected at three and six weeks of age and analysed using ELISA, flow cytometry, haematology and biochemistry. Results: On the 42nd dol, as the content of larvae meal in the chickens' diets increased, the birds' body weights decreased significantly. The substitution of the protein source had no effect on the haematological markers. In chicks that received larvae meal, there was a decrease in creatine kinase activity and phosphorus levels and an increase in calcium and uric acid levels in serum. Raising the proportion of full-fat HI larvae meal in the diet raised the percentage of T CD3+CD8a+ cells and lowered that of T CD3+CD4+ cells in both sample types. Chickens fed larvae meal had significantly lower post-vaccination anti-infectious bronchitis virus antibody titres. Conclusion: The poorer production results and impaired health in experimental birds may indicate lower than 50% protein substitution with full-fat HI larvae meal to be optimal.

The effect of early administration of antibiotics or feeding a diet containing a coccidiostat on inflammatory responses and the morphological structure of selected organs of the immune system in young meat-type turkeys.

It was assumed that early administration of enrofloxacin or doxycycline may impair immune function and alter the morphology of organs of the immune system in turkeys, and that diets containing the coccidiostat monensin, an ionophore antibiotic, can exert similar effects. The aim of this study was to determine whether early antibiotic administration or feeding a diet containing a coccidiostat affect immune function in young turkeys. The experiment had a completely randomized design, with 8 groups (a total of 3,080 one-day-old turkeys), 7 replicate pens per group and 55 birds per pen. The experiment had a 2-factorial design, with 4 treatments (C-control, M-monensin, E-enrofloxacin, and D-doxycycline) and 2 groups of birds (vaccinated and unvaccinated) per treatment. Control group birds did not receive the coccidiostat or antibiotics. Group M was administered monensin at 90 mg/kg feed for the first 5 d of life, group E received enrofloxacin at 10 mg/kg BW, added to drinking water, for the first 5 d of life, and group D received doxycycline at 50 mg/kg BW, added to drinking water, for the first 5 d of life. One-day old turkeys from groups C+, M+, E+, and D+ were administered live-attenuated vaccines against turkey rhinotracheitis (TRT) (Poulvac TRT; Zoetis, Parsippany, NJ) and Newcastle disease (ND) (Nobilis ND clone 30; Merck, Rahway, NJ) by coarse spray; 28-day-old birds were administered a subcutaneously injected inactivated vaccine against Ornithobacterium rhinotracheale (ORT) (Ornitin, Phibro, Poland). Turkeys from groups C-, M-, E-, and D- were not vaccinated. It was found that early administration of enrofloxacin or doxycycline, or feeding a diet containing monensin, did not weaken the immune system of turkeys. The administration of monensin, in particular when combined with vaccination, was least effective in inhibiting inflammatory responses. Histological changes in immunocompetent organs (fatty degeneration) were also most severe in birds receiving monensin, followed by those administered doxycycline and enrofloxacin. The observed changes were exacerbated by vaccination.

Increased arginine, lysine, and methionine levels can improve the performance, gut integrity and immune status of turkeys but the effect is interactive and depends on challenge conditions.

Arginine (Arg), lysine (Lys), and methionine (Met) can be used to support the health status of turkeys. The present study investigated selected performance, gut integrity, and immunological parameters in turkeys reared in optimal or challenge conditions. The experiment lasted for 28 days, and it had a completely randomized 2 × 3 factorial design with two levels of dietary Arg, Lys and Met (high or low) and challenge with Clostridium perfringens (C. perfringens), Escherichia coli lipopolysaccharide (LPS) or no challenge (placebo). Increased dietary levels of Arg, Lys and Met had a beneficial effect on turkey performance and immunological parameters, and it improved selected indicators responsible for maintaining gut integrity in different challenge conditions. Under optimal conditions (with no challenge), high ArgLysMet diets did not compromise bird performance and they improved selected performance parameters in challenged birds. The immune system of turkeys was not excessively stimulated by high ArgLysMet diets, which did not disrupt the redox balance and had no negative effect on gut integrity. High ArgLysMet diets increased the expression levels of selected genes encoding nutrient transporters and tight junction proteins. However, the influence exerted by different dietary inclusion levels of Arg, Lys and Met on gut integrity was largely determined by the stressor (C. perfringens vs. LPS). Further studies are required to investigate the role of Arg, Lys and Met levels in the diet on the immune response, gut function and performance of turkeys in different challenge conditions.

Immune Parameters in Chickens Treated with Antibiotics and Probiotics during Early Life.

The aim of the study was to compare the effect of the administration of antibiotics or probiotics on chickens in their first week of life, on selected parameters of humoral and cellular immunity, and on the bursa of Fabricius and spleen indices. The experiment was carried out on 90 one-day-old male broilers. The control group received no additive in the drinking water; the group GP received a probiotic providing Enterococcus faecium and Bacillus amyloliquefaciens; and the group GA received 10% enrofloxacin in the drinking water on the first five days of life. Administration of the antibiotic enrofloxacin or a probiotic containing E. faecium and B. amyloliquefaciens strains to chickens in their first week of life exerts pronounced immunomodulatory effects on humoral and cellular defense mechanisms in these birds. The changes in the subpopulations of B and T cells immediately following early administration of enrofloxacin or the probiotic were not observed at the age of 35 days. Early administration of enrofloxacin can pose a risk of suppression of humoral immunity, as indicated by the significant decrease in the total IgY concentration in the plasma of the chickens.

Effect of Immunomodulation in Turkeys Infected with Haemorrhagic Enteritis Virus on the Percentage of CD4+ and CD8α+ T Lymphocyte Subpopulations Synthesising IFN-γ.

Introduction: Haemorrhagic enteritis virus (HEV) is a common turkey pathogen which suppresses the immune function. The immunosuppressive potential of both field and vaccine strains of HEV makes it necessary to seek substances which can limit or prevent this phenomenon. The aim of the presented work was to investigate the effect of two immunomodulators in the immune response of HEV-infected turkeys. The immunomodulators were synthetic methisoprinol and a natural preparation containing 34.2% ß-glucans (ß-1,3/1,6) and 12% mannan oligosaccharides (MOS). Material and Methods: The synthetic immunomodulator was administered to female Big 6 turkey chicks at a dose of 200 mg/kg b.w. in drinking water i) for 3 days before, ii) for 5 days after, or iii) for 3 days before, on the day of infection, and for 5 days after experimental HEV infection in turkeys. The natural counterpart was also given to female Big 6 turkey chicks at a dose of 500 g/tonne of feed i) for 14 days before, ii) for 5 days after, or iii) for 14 days before, on the day of infection, and for 5 days after infection. Their effect was evaluated on the synthesis of interferon gamma (IFN-γ) by splenic CD4+ and CD8α+ T cells in response to mitogen stimulation in vitro. Samples were taken 3, 5 and 7 days after infection and analysed by intracellular cytokine staining assay. Results: Methisoprinol was shown to increase the CD4+IFN-γ+ and CD8α+IFN-γ+ T cell count in these birds over the same cell count in control turkeys. A similar effect was obtained in turkeys that received the natural immunomodulator. Conclusion: The evaluated immunomodulators may be used to attenuate the effects of immunosuppression in HEV-infected turkeys.

Effect of a Mineral-Microbial Deodorizing Preparation on the Functions of Internal Organs and the Immune System in Commercial Poultry.

Animal production is identified as one of the main sources of high concentrations of odours, which are related to air pollution, health problems of living organisms and indirect negative impact on production results. One common method for reducing emissions of ammonia is using preparations containing probiotics and hygroscopic or disinfecting compounds. This study was undertaken in order to determine the impact of innovative mineral-microbial deodorizing preparation, which reduces odorous gases, applying to the litter once a week in poultry houses on the physiological status of breeder chickens, broiler chickens and turkeys. Samples were collected after slaughter and analyzed using ELISA tests, flow cytometry and biochemical methods. Biochemical markers of the liver and kidney profile (ALT, AST, LDH, ALP, CK, TP, CALC, PHOS) and the titers of specific antibodies against AEV, aMPV, AAvV-1, IBDV, HEV, BA were analyzed in serum samples. The percentage contribution of T and B lymphocyte subpopulations was determined in the samples of tracheal mucosa, blood, and spleen. No significant differences were found between the control and experimental group with regard to all the analyzed parameters, with some exceptions for biochemistry. The results of our study indicated that mineral-microbial deodorizing preparation did not affect the physiological status of birds.

The immune status, oxidative and epigenetic changes in tissues of turkeys fed diets with different ratios of arginine and lysine.

In the present experiment, it was assumed that the appropriate dietary ratio of arginine (Arg) to lysine (Lys) can improve the immune status and growth performance of turkeys. The aim of this study was to evaluate the effects of two inclusion rates of Arg relative to Lys in turkey diets with Lys content consistent with National Research Council (NRC) recommendations or 10% higher on the immune status of birds and indicators of protein and DNA damage due to oxidation, nitration or epigenetic changes. Another goal was to determine which dietary Arg:Lys ratio stimulates the immune response of turkeys vaccinated against Ornithobacterium rhinotracheale. The experiment was performed on 576 turkeys randomly assigned to four groups with two levels of Lys (low = NRC recommendation or high = NRC + 10%) and two levels of Arg (95% or 105% Arg relative to the content of dietary Lys). It was found that the Lys content of turkey diets should be 10% higher than that recommended by the NRC and combined with the higher Arg level (105% of Lys). Although the above Arg:Lys ratio did not improve the growth performance of birds, it stimulated their immune system and reduced protein nitration as well as protein and DNA oxidation.

Phytoncides in The Prevention and Therapy of Blackhead Disease and Their Effect on The Turkey Immune System.

INTRODUCTION: Turkey histomonosis poses a serious threat to poultry production due to the ban on the use of effective drugs. The aim of the study was to evaluate the influence of a phytoncidal feed supplement on the course of histomonosis. The preparation was also analysed for immunomodulatory properties. MATERIAL AND METHODS: Clinical observations and production monitoring were conducted in a flock of turkeys with histomonosis from their 11th to 56th weeks of life which were treated with the adiCoxSOLPF soluble supplement in a dose of 2.5 mL/L water. Later the preparation was used in a preventive dose (1 mL/L). The influence on the immune system was evaluated in broiler turkeys having been given adiCoxSOLPF for 3 days in doses of 1 or 3 mL/L. The T and B lymphocyte percentages in turkey blood and spleen tissue were analysed with flow cytometry. ELISA was implemented to evaluate antibody titres after Ornithobacterium rhinotracheale vaccination, and biochemical analyses were performed to evaluate the supplement's safety. RESULTS: AdiCoxSOLPF was found effective in therapy and prevention of histomonosis. Additionally, adiCoxSOLPF stimulated both humoral and cell-mediated immune mechanisms, without impairing the functions of internal organs. The treated turkeys also yielded better production results (eggs/hen, fertility, and hatchability). CONCLUSION: AdiCoxSOLPF possesses immunomodulatory properties and it can be used successfully in the prevention and therapy of histomonosis in turkeys.

The influence of maternally derived antibodies on protection against aMPV/A infection in TRT vaccinated turkeys.

Avian metapneumoviruses (aMPV) are a causative agent of turkey rhinotracheitis (TRT). Despite vaccination, cases of TRT outbreaks are frequently reported. Considering that there are aMPV-free areas, a part of turkey poults possess (MDA+) or do not possess (MDA-) maternally derived antibodies (MDA) in the first weeks of life, which is the time of TRT vaccination. Study was undertaken to establish the level of protection against homologue aMPV/A infection, in MDA+ and MDA- turkeys, vaccinated against TRT at the 0 or 14th d of life and infected 14 d later. With the use of ELISA test and qPCR techniques, we have established the level of immune system stimulation after the vaccination and how does it correlate with the level of protection against the aMPV infection. Vaccination of MDA+ turkeys (especially at 0 d of life) resulted in weaker IgA production in upper respiratory tract. In addition, we have demonstrated differences in both humoral and cell-mediated immunity stimulation after infection of vaccinated turkeys. Despite these differences, we have shown that all vaccinated birds were protected against the disease which was determined based on the clinical and histopathological scoring, as well as the level of aMPV/A replication and shedding. Nonvaccinated groups of turkeys displayed typical signs of TRT after infection which indicates that MDA alone are incapable of preventing the disease. Differences in TRT course were recorded between different age groups of nonvaccinated birds. Birds infected at the 28th d of life (especially MDA- birds) developed more severe signs, and the level of aMPV replication was higher than that in birds infected on the 14th d of life. Despite the minor role in alleviating TRT course, MDA seems not to interfere with the vaccination efficacy. It is hard to predict whether the observed immune system stimulation differences between MDA+ and MDA- birds after vaccination can influence the outcome of vaccination efficacy under the field conditions.

The Clinical Infection with Pigeon Circovirus (PiCV) Leads to Lymphocyte B Apoptosis But Has No Effect on Lymphocyte T Subpopulation.

The pathology of pigeon circovirus (PiCV) is still unknown, but it is regarded as an immunosuppressant. This study aimed to find a correlation between PiCV natural infection and immunosuppression. The study was conducted with 56 pigeons divided into the following groups: PiCV-positive but showing (group S) or not (group I) non-specific clinical symptoms and asymptomatic pigeons negative for PiCV (group H). The percentage and apoptosis of T CD3+ and B IgM+ splenocytes; the expression of CD4, CD8, and IFN-γ genes in splenic mononuclear cells; the number of PiCV viral loads in the bursa of Fabricius; and the level of anti-PiCV antibodies were analyzed. The results showed that the percentage of B IgM+ cells was almost two-fold lower in group S than in group H, and that ca. 20% of the lymphocytes were apoptotic. No increased apoptosis was detected in TCD3+ subpopulation. The PiCV viral loads were approximately one thousand and ten thousand times higher in group S than in groups I and H, respectively. Our results indicate a possible correlation between the number of PiCV viral loads and severity of PiCV infection and confirm that PiCV infection leads to the suppression of humoral immunity by inducing B lymphocyte apoptosis.

IFNγ Production Profile in Turkeys of Different Immunological Status after TRT Vaccination.

INTRODUCTION: Despite vaccination against avian metapneumoviruses (aMPV), cases of turkey rhinotracheitis (TRT) caused by aMPV field strains are frequently reported. Differences have been shown in the level of immune system stimulation after aMPV vaccination between turkeys that do and do not possess specific anti-aMPV maternally derived antibodies (MDA). The article describes the influence of MDA on the production of IFNγ in the spleen of aMPV-vaccinated turkeys. MATERIAL AND METHODS: MDA+ or MDA- turkeys were vaccinated against TRT after hatching or on the 14th day of life. Spleen samples were collected 3, 7, and 14 days post vaccination for mononuclear cell isolation. Real-time PCR, flow cytometry, and the enzyme-linked immunospot assay were used to evaluate the levels of IFNγ gene expression, production, and secretion by cells within the spleen samples. RESULTS: Increased IFNγ gene expression was noticed after vaccination only in birds that did not possess MDA or possessed MDA at relatively low level (MDA+ birds vaccinated at 14 DOL). In all birds, an increased percentage of T lymphocytes producing IFNγ was recorded. The proportion of anti-aMPV IFNγ-secreting cells was increased only in MDA- birds. CONCLUSION: Besides having a protective role, MDA are known to interfere with vaccination efficacy. The analysis of our results confirms that MDA can decrease the level of immune system stimulation after aMPV vaccination of turkeys.

Research Note: Effect of age on the distribution of lymphocytes in the oviduct in Turkey breeder hens.

Considering the lack of research on the local immunity of the reproductive tract in other poultry species than chickens, the aim of this study was to determine the contribution of T and B cell subpopulations in different parts of breeder turkey oviduct mucous membrane with the use of flow cytometry. In addition, the study aimed to establish an impact of bird age and different stages of the egg production cycle on the systemic and local oviduct-related immune system structure. Our study results demonstrated a lower percentage of T lymphocytes in 32-wk turkey hens followed by a successively increasing population of these cells up to the 38th week of bird's life. The results of our study have also shown a similar dependency between birds' age and number of B lymphocytes. In addition, we demonstrated a decrease in the number of immune system cells in the oviduct, blood, and spleen of turkey hens in the late and end laying period. The differences reported in the number of lymphocyte subpopulations in the reproductive system of laying turkey hens at various stages of the production cycle may, to some extent, explain the frequency and periods of increased predilection to the incidence of infectious diseases in birds under field conditions.

The immune response of young turkeys to haemorrhagic enteritis virus infection at different levels and sources of methionine in the diet.

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.

Comparison of the immune response to vaccination with pigeon circovirus recombinant capsid protein (PiCV rCP) in pigeons uninfected and subclinically infected with PiCV.

Infections with immunosuppressive pigeon circovirus (PiCV) pose the most severe health problem to the global pigeon breeding. The vaccination with immunogenic PiCV recombinant capsid protein (PiCV rCP) is a potential tool for disease control. Because of the high prevalence of PiCV asymptomatic infections, the subclinically infected pigeons will be vaccinated in practice. The aim of this study was to answer a question if vaccination of asymptomatic, infected with PiCV pigeons induces a similar immune response to PiCV rCP as in uninfected birds. One hundred and twenty 6-week-old carrier pigeons were divided into 4 groups (2 groups of naturally infected and uninfected with PiCV individuals). Birds from groups V and V1 were vaccinated twice with PiCV rCP mixed with an adjuvant, whereas pigeons from groups C and C1 were immunized with an adjuvant only. The expression of genes encoding IFN-γ, CD4, and CD8 T lymphocyte receptors; the number of anti-PiCV rCP IgY-secreting B cells (SBC) and anti-PiCV rCP IgY were evaluated 2, 21, 39 and 46 days post vaccination (dpv). Study results showed that the expression of CD8 and IFN-γ genes was higher in both groups of infected pigeons than in the uninfected birds, irrespective of vaccination. In the uninfected birds, the expression of these genes was insignificantly higher in the vaccinated pigeons. The anti-PiCV rCP IgY-SBC were detected on 2 and 23 dpv and seroconversion was noted on 23 and 39 dpv in V and V1 groups, respectively. In the light of the results obtained, it could be concluded that pigeon circovirus recombinant capsid protein elicits the immune response in both naturally infected and uninfected pigeons, but its rate varies depending on PiCV infectious status. The infection with PiCV masks the potential cellular immune response to the vaccination with PiCV rCP and leads to the suppression of humoral immunity.

Field evaluation of maternal antibody transfer from breeder turkey hens to egg yolks, egg whites, and poults.

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.

The effect of different dietary levels of DL-methionine and DL-hydroxy analogue on the antioxidant status of young turkeys infected with the haemorrhagic enteritis virus.

BACKGROUND: The results of experiments involving broiler chickens and turkeys indicate that increased dietary methionine (Met) levels may improve the antioxidant protection of tissues in fast-growing birds. This is an important consideration since viral infections induce oxidative stress. The aim of this study was to verify the hypothesis that turkey diets with increased Met content can suppress oxidation processes induced by infection caused by the haemorrhagic enteritis virus (HEV), and that the noted effect is determined by the chemical form of this amino acid: DL-methionine (DLM) or DL-hydroxy analogue of Met (MHA). RESULTS: Dietary Met content above 40% higher than the level recommended by the NRC (1994) intensified lipid peroxidation in the small intestine, leading to an increase in malondialdehyde (MDA) and lipid peroxide (LOOH) levels, but it also stimulated antioxidant mechanisms in the blood and liver of turkeys infected with HEV. In comparison with DLM, MHA contributed to more severe symptoms of oxidative stress, such as elevated MDA levels in the intestines, and a decrease in glutathione peroxidase (GPx) activity and ferric-reducing ability of plasma (FRAP). CONCLUSIONS: In HEV-infected turkeys, diets with increased Met content did not exert a clear antioxidant effect, which was noted in uninfected birds. The prooxidant activity of Met observed in the small intestinal wall was suppressed in the blood and liver of turkeys, most likely due to intensified synthesis of uric acid and glutathione. In comparison with MHA, DLM had a more beneficial influence on the analysed parameters of the redox status in the small intestine, blood and liver of turkeys.

Immunogenicity of Pigeon Circovirus Recombinant Capsid Protein in Pigeons.

Pigeon circovirus (PiCV) is the most frequently diagnosed virus in pigeons and is thought to be one of the causative factors of a complex disease called the young pigeon disease syndrome (YPDS). The development of a vaccine against this virus could be a strategy for YPDS control. Since laboratory culture of PiCV is impossible, its recombinant capsid protein (rCP) can be considered as a potential antigen candidate in sub-unit vaccines. The aim of this basic research was to evaluate the immune response of pigeons to PiCV rCP. Sixty six-week-old carrier pigeons were divided into two groups (experimental immunized with PiCV rCP mixed with an adjuvant, and control immunized with an adjuvant only), and immunized twice in a 21-day interval. On the day of immunization and on two, 23, 39, and 46 days post first immunization (dpv), samples of blood, spleen, and bursa of Fabricius were collected from six birds from each group to examine anti-PiCV rCP IgY, anti-PiCV rCP IgY-secreting B cells (SBC), IFN-γ gene expression, and percentage of T CD3⁺, CD4⁺, CD8⁺, and B IgM⁺ lymphocytes. The results indicated a correct immune response to PiCV rCP both in humoral and cell-mediated immunity, which was manifested by seroconversion since 23 dpv, by a significantly higher anti-PiCV rCP IgY-SBC number on two and 23 dpv, and significantly higher IFN-γ gene expression since two dpv. There were no significant differences or trends noted between particular T and B lymphocyte subpopulations. To conclude, PiCV rCP may be deemed immunogenic and could be considered as an antigen candidate in sub-unit vaccines against PiCV infections in pigeons.

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.

Immunological aspects of the efficiency of protectotype vaccination strategy against chicken infectious bronchitis.

BACKGROUND: One of the most commonly applied protectotype vaccination protocol against infectious bronchitis (IB) in broiler chickens in the EU is simultaneous or alternate use of Ma5 and 4/91 vaccine strains. After IB vaccination and infection, systemic and upper respiratory tract (URT), humoral and cell-mediated immunity (CMI), are stimulated. The level of this stimulation correlates with the level of protection against IB. RESULTS: We've investigated the development of URT and systemic, cell-mediated and humoral immunity in commercial broiler chickens vaccinated with Ma5 and/or 4/91 strains at hatch day. We've demonstrated that the group vaccinated with Ma5 and 4/91 strain simultaneously developed the most desirable immunity which reflects the level of CD8+ T cells stimulation in spleen and Harderian gland, as well as the level of IgA and IgY in URT washings and serum and their cross-reactivity with 7 IBV strains. CONCLUSIONS: Although we did not demonstrate directly why Ma5 + 4/91 protocol is so efficient it seems that it combines the benefits of monovalent vaccination with either Ma5 or 4/91 and while Ma5 seems to stimulate CMI more efficiently, the 4/91 strain generates a wider spectrum of immune system cross-reactivity and higher URT IgA production.