Caecal Tonsils Research Articles

The 60S ribosomal protein L13 is the most preferable reference gene to investigate gene expression in selected organs from turkeys and chickens, in context of different infection models.

Evaluation of reference genes for expression studies in chickens and turkeys is very much limited and unavailable for various infectious models. In this study, eight candidate reference genes HMBS, HPRT1, TBP, VIM, TFRC, RPLP0, RPL13 and RPS7 were evaluated by five different algorithms (GeNorm, NormFinder, BestKeeper©, delta CT, RefFinder) to assess their stability. In order to analyze a broad variation of tissues, spleen, liver, caecum and caecal tonsil of different aged specific pathogen free (SPF) layer chickens and commercial turkeys, uninfected or infected with the extracellular pathogen Histomonas meleagridis, were included. For tissue samples from SPF chickens RPL13 and TBP were found to be the most stable reference genes. Further testing of RPL13 and TBP in the same organs of uninfected and infected SPF broiler chickens with the intracellular pathogen fowl aviadenovirus confirmed this finding. In tissue samples from turkeys, a stable expression of RPL13 and TFRC genes was noticed. Overall, the determined reference genes should be considered whenever gene expression studies in spleen, liver, caecum and caecal tonsil of chickens and turkeys are performed.Electronic supplementary materialThe online version of this article (doi:10.1186/s13567-016-0388-z) contains supplementary material, which is available to authorized users.

Phylogeny and S1 Gene Variation of Infectious Bronchitis Virus Detected in Broilers and Layers in Turkey.

The avian coronavirus infectious bronchitis virus (AvCoV-IBV) is recognized as an important global pathogen because new variants are a continuous threat to the poultry industry worldwide. This study investigates the genetic origin and diversity of AvCoV-IBV by analysis of the S1 sequence derived from 49 broiler flocks and 14 layer flocks in different regions of Turkey. AvCoV-IBV RNA was detected in 41 (83.6%) broiler flocks and nine (64.2%) of the layer flocks by TaqMan real-time RT-PCR. In addition, AvCoV-IBV RNA was detected in the tracheas 27/30 (90%), lungs 31/49 (62.2%), caecal tonsils 7/22 (31.8%), and kidneys 4/49 (8.1%) of broiler flocks examined. Pathologic lesions, hemorrhages, and mononuclear infiltrations were predominantly observed in tracheas and to a lesser extent in the lungs and a few in kidneys. A phylogenetic tree based on partial S1 sequences of the detected AvCoV-IBVs (including isolates) revealed that 1) viruses detected in five broiler flocks were similar to the IBV vaccines Ma5, H120, M41; 2) viruses detected in 24 broiler flocks were similar to those previously reported from Turkey and to Israel variant-2 strains; 3) viruses detected in seven layer flocks were different from those found in any of the broiler flocks but similar to viruses previously reported from Iran, India, and China (similar to Israel variant-1 and 4/91 serotypes); and 4) that the AVCoV-IBV, Israeli variant-2 strain, found to be circulating in Turkey appears to be undergoing molecular evolution. In conclusion, genetically different AvCoV-IBV strains, including vaccine-like strains, based on their partial S1 sequence, are circulating in broiler and layer chicken flocks in Turkey and the Israeli variant-2 strain is undergoing evolution.

The Unusual Resistance of Avian Defensin AvBD7 to Proteolytic Enzymes Preserves Its Antibacterial Activity.

Defensins are frontline peptides of mucosal immunity in the animal kingdom, including birds. Their resistance to proteolysis and their ensuing ability to maintain antimicrobial potential remains questionable and was therefore investigated. We have shown by bottom-up mass spectrometry analysis of protein extracts that both avian beta-defensins AvBD2 and AvBD7 were ubiquitously distributed along the chicken gut. Cathepsin B was found by immunoblotting in jejunum, ileum, caecum, and caecal tonsils, while cathepsins K, L, and S were merely identified in caecal tonsils. Hydrolysis product of AvBD2 and AvBD7 incubated with a panel of proteases was analysed by RP-HPLC, mass spectrometry and antimicrobial assays. AvBD2 and AvBD7 were resistant to serine proteases and to cathepsins D and H. Conversely cysteine cathepsins B, K, L, and S degraded AvBD2 and abolished its antibacterial activity. Only cathepsin K cleaved AvBD7 and released Ile4-AvBD7, a N-terminal truncated natural peptidoform of AvBD7 that displayed antibacterial activity. Besides the 3-stranded antiparallel beta-sheet typical of beta-defensins, structural analysis of AvBD7 by two-dimensional NMR spectroscopy highlighted the restricted accessibility of the C-terminus embedded by the N-terminal region and gave a formal evidence of a salt bridge (Asp9-Arg12) that could account for proteolysis resistance. The differential susceptibility of avian defensins to proteolysis opens intriguing questions about a distinctive role in the mucosal immunity against pathogen invasion.

Prevalence and pathology of Newcastle disease in broiler at Bochaganj Upazila of Dinajpur, Bangladesh

The study was schemed to investigate the prevalence, pathological conditions, mortality and clinical features of Newcastle disease in the small scale commercial broiler farms at Bochaganj upazila of Dinajpur district during January to June, 2014. A total 1950 birds (from 5 farms), among which 160 diseased and dead birds were selected out of which 99 (5.35%) birds were found to be positive for Newcastle disease. The clinical signs of the affected birds were sneezing, coughing, nasal discharge, laboured breathing, and torticolis. Broiler were inactive, weak and rough in appearance, greenish watery diarrhoea occur severely. Nervous sign include clonic, spasm and paralysis of the legs and wings. In this observation, the gross pathological lesions were slight to severe haemorrhages in caecal tonsils, typical lesions were proventricular haemorrhage, most commonly seen in the surface near the junction with the proventriculus. The prevalence of Newcastle disease in Bochaganj upazila was 5.35%. Mortality of Newcastle disease in non-vaccinated and vaccinated broiler flock was 20.76% and 4.6%, respectively.Asian J. Med. Biol. Res. June 2016, 2(2): 352-356

Effect of route of inoculation on replication of avian influenza virus (H9N2) and interferon gene expression in guinea fowl (Numida meleagridis)

The study was designed to investigate the replication of a re-assortant H9N2 avian influenza virus (AIV) and induction of the interferon (IFNγ) response after aerosol or intranasal inoculation with the virus in guinea fowl. To determine virus shedding pattern, oropharyngeal and cloacal swabs and tissue specimens of trachea, lungs, spleen and caecal tonsils were collected post-inoculation (pi).Infected guinea fowl showed mild clinical signs, while negative control guinea fowl remained healthy and active throughout the experiment irrespective of the inoculation route. However, the clinical signs were more prominent in guinea fowl infected through the aerosol route.Virus was detected in all oropharyngeal and cloacal swabs up to 7 d pi in guinea fowl from both inoculation groups. However, virus was detected more frequently and in higher titres in oropharyngeal swabs and specimens of trachea and lungs from the group exposed to aerosols than in the group given intranasal drops.In accordance with viral replication findings, expression of IFNγ was up-regulated on 1, 2 and 4 d pi to a significantly higher level in lung tissue specimens from the group exposed to virus aerosol than from controls treated with PBS intranasally. On the other hand, IFNγ was up-regulated above that of controls in lung tissue specimens from the group treated with intranasal drops of virus only on 4 d pi.These findings indicate that virus administered in aerosols was more efficient in infecting the lower respiratory tract and in inducing activity of the IFNγ gene than virus administered as intranasal drops. The results of this study suggest that virus aerosols cause more intense respiratory infection and increase the shedding of the H9N2 AIV in guinea fowl, highlighting the potential role of guinea fowl as a mixing bowl for transmission and maintenance of H9N2 AIV between poultry premises.

Probiotic feeding affects T cell populations in blood and lymphoid organs in chickens.

This study was performed to evaluate the effects of Lactobacillus acidophilus bacteria as a probiotic on chicken T cell subset populations in peripheral blood and lymphoid tissues. Thirty chickens were divided into three groups and fed sterilised cow milk, a mixture of milk and L. acidophilus (probiotic), or neither, as the control group. Chickens were euthanised after 14 and 21 days, and whole blood and ileal, bursal, and caecal tonsillar tissues were collected. The populations of T cell subsets, including CD4+, CD8+, and TCR1+ cells, were evaluated by immunohistochemistry and flow cytometry. After 21 days of treatment the percentage of blood CD4+, CD8+, and TCR1+ cells was significantly higher in the probiotic-fed group than in the control group. After 14 days of treatment, a significantly greater number of CD4+ T cells were found in the ileum of probiotic-fed chickens than in chickens from the other two groups. This difference was even greater after 21 days. In addition, after 21 days, a significantly greater number of TCR1+ cells were found in the caecal tonsils of milk-fed chickens than in chickens from the control group. The findings indicate that probiotics may alter the distribution of T cells in the blood and lymphoid tissues in young chickens; however, transient changes in lymphoid tissues indicate that probiotics likely do not permanently affect mucosal immunity.

Experimental infection of chickens by a flagellated motile strain of Salmonella enterica serovar Gallinarum biovar Gallinarum

Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum (SG) causes fowl typhoid (FT), a septicaemic disease which can result in high mortality in poultry flocks. The absence of flagella in SG is thought to favour systemic invasion, since bacterial recognition via Toll-like receptor (TLR)-5 does not take place during the early stages of FT. In the present study, chicks susceptible to FT were inoculated with a wild type SG (SG) or its flagellated motile derivative (SG Fla+). In experiment 1, mortality and clinical signs were assessed, whereas in experiment 2, gross pathology, histopathology, systemic invasion and immune responses were evaluated. SG Fla+ infection resulted in later development of clinical signs, lower mortality, lower bacterial numbers in the liver and spleen, and less severe pathological changes compared to SG. The CD8+ T lymphocyte population was higher in the livers of chicks infected with SG at 4 days post-inoculation (dpi). Chicks infected with SG had increased expression of interleukin (IL)-6 mRNA in the caecal tonsil at 1 dpi and increased expression of IL-18 mRNA in the spleen at 4 dpi. In contrast, the CD4+ T lymphocyte population was higher at 6 dpi in the livers of birds infected with SG Fla+. Therefore, flagella appeared to modulate the chicken immune response towards a CD4+ T profile, resulting in more efficient bacterial clearance from systemic sites and milder infection.

Effects of dietary acidifier supplementation on broiler growth performance, digestive and immune function indices

The effect of dietary acidifier (AC) supplementation in combination or not with avilamycin (AV) was evaluated on broiler performance, nutrient digestibility, gizzard pH, activity of digestive enzymes and relative expression of cytokines. A 2 × 2 factorial experimental design with inclusion of AC (0 and 1 g/kg of diet) and AV (0 and 2.5 mg/kg of diet) as the main factors was implemented. Subsequently, 544-day-old male Cobb broilers were allocated in four treatments (i.e. C – no additions, AC; AV and ACAV), each having eight replicates of 17 broilers, for 6 weeks. Overall bodyweight gain (BWG) was improved (PAC = 0.035) by AC addition. BWG and feed conversion ratio were improved (P ≤ 0.05) by AV addition in all growth periods and overall. Dry matter, organic matter digestibility and energy retention were improved by AC (PAC = 0.050, PAC = 0.045 and PAC = 0.020, respectively), or AV (PAV = 0.018, PAV = 0.013 and PAV = 0.012, respectively). In addition AV supplementation improved digestibility of ether extracts (PAV = 0.022) and crude protein (PAV = 0.042). Pancreatic trypsin activity was lower in AC (PAC = 0.027) or AV (PAV ≤ 0.001) supplemented diets. An AC × AV effect on gizzard pH (PAC × AV = 0.034) was noted. Expression of interferon-γ (PAV = 0.010), interleukin (IL) 18 (PAV = 0.048) and inducible nitric oxide synthase 2 (PAV = 0.035) in spleen were downregulated by AV. An upregulation of IL10 (PAC × AV = 0.018), IL18 (PAC × AV = 0.002) and IL22 (PAC × AV = 0.030) in the caecal tonsils was shown for the combined ACAV supplementation. In conclusion, dietary AC supplementation improved performance, nutrient digestibility and energy retention, irrespective of AV inclusion. This study has provided evidence for potential links between digestive and immune function indices with growth performance improvements.

Dietary inclusion level effects of a phytogenic characterised by menthol and anethole on broiler growth performance, biochemical parameters including total antioxidant capacity and gene expression of immune-related biomarkers

The supplementation of a phytogenic feed additive (PFA) characterised by menthol and anethole was evaluated at three levels on broiler growth performance, nutrient digestibility, biochemical parameters, total antioxidant capacity of plasma, breast and thigh meat as well as on the relative gene expression of immune-related biomarkers. A total of 225 1-day-old male Cobb-500 were assigned into three treatments with five replicates of 15 chicks each. Wheat-soybean meal basal diets were formulated according to a three-phase (i.e. starter, grower and finisher) feeding program. Dietary treatments were: no PFA, PFA at 100 mg/kg diet and PFA at 150 mg/kg diet. Feed and water were available ad libitum. Performance parameters were monitored weekly and all other biological responses were determined at 42 days of broiler age. Increasing PFA level increased (P = 0.044) bodyweight gain at finisher period, decreased quadratically (P = 0.035) overall feed intake, and quadratically improved (P = 0.024) overall feed conversion ratio. Moreover, increasing PFA level increased plasma total antioxidant capacity linearly (P = 0.001) whereas linearly decreased (P = 0.005) triglyceride concentration. Thigh meat cholesterol decreased linearly (P = 0.016) with increasing PFA level. Expression of pro-inflammatory cytokine IL-2 in caecal tonsils increased quadratically (P = 0.046) with increasing PFA level. In conclusion, PFA inclusion at 100 mg/kg diet affected positively performance whereas a stronger improvement mainly in plasma total antioxidant capacity and triglyceride as well as in meat cholesterol was noted for the 150 mg/kg diet level. Inclusion of PFA resulted in increasing pro-inflammatory biomarker IL-2 at local caecal level.

Effect of Dietary Inclusion of Black Cumin (Nigella sativa) Seeds on Histological Parameters of Caecal Tonsils and Bursa of Fabricius in Broiler Chickens

This study aimed to evaluate the effect of long term administration of Nigella sativa seed as an herbal immunomodulatory agent on histological features of caecal tonsils and bursa of Fabricius in broiler chickens. Fifty, one-day old chick were randomly divided into five equal groups and fed with diets containing 0, 0.5, 1, 1.5, and 2% of N. sativa seedsfor 45 days. Then birds were slaughtered and 6μm-thick cross sections were made from caecal tonsils and bursa of Fabricius and stained with hematoxylin and eosin. Villus height and villus basal width, nodular unit width and height, follicular width and muscular layer width in caecal tonsils as well as height of plicae, follicular width, thickness of follicular cortex and medulla in bursa were determined. In addition, number of follicles in each plica in bursa of Fabricius and number of follicles per nodular unit in caecal tonsils were determined under light microscope. The results showed a change in all histomorphometric parameters of caecal tonsils due to N. sativa administration which followed a dose-dependent pattern in most cases. Villus height, nodular unit width and muscular layer width were decreased while other parameters increased as compared to control. Although all parameters in bursa increased due to N. sativa seed administration, plica height was the only parameter which showed a dose-dependent change. In conclusion, dietary inclusion of N .sativa especially at 2% dose, can improve immune structures of both bursa of Fabricius and caecal tonsils of broilers.

Viral quantity and pathological changes in broilers experimentally infected by IRFIBV32 isolate of infectious bronchitis virus.

An Iranian isolate of avian infectious bronchitis virus IRFIBV32 was quantified in experimentally infected broilers using real-time reverse transcriptase polymerase chain reaction and histopathological changes was investigated. Thirty-six 3-week-old commercial broilers were inoculated by 105 ELD50/0.1 ml of the virus. On the various days post inoculation (dpi) different tissues were collected. The virus strongly started the replication in trachea at 1 dpi and reached to the maximum titer at 3 dpi. The highest IBV RNA level was shown in this organ. In lung, the virus was replicated with the titer lower than that of the trachea, but it rose up more at 5 dpi. The kidneys were the tissues with the least viral genome copy number, although the duration of the virus presence was considerable. The virus replicated in testes sooner than ovaries also disappeared sooner but the maximum viral yield in the ovaries was more. The virus titer in the studied tissues had an interesting fluctuation especially in caecal tonsils. Testes and ovaries were the organs that the virus could reactivate without using any chemical. The most severe lesions were observed in tracheae but they appeared in the lungs later. Lymphocyte infiltration in the kidneys was noted from 5 dpi even sooner than the lungs. There were no lesions in the caecal tonsils, testes and ovaries in spite of the virus replication in a high titer.

Modulation of cytokine gene expression by selected Lactobacillus isolates in the ileum, caecal tonsils and spleen of Salmonella-challenged broilers

Probiotics have been used to control Salmonella colonization in the chicken intestine. Recently, we demonstrated that certain selected Lactobacillus isolates were able to reduce Salmonella infection in the chicken spleen and liver as well as down-regulated Salmonella pathogenicity island 1 virulence gene expression in the chicken caecum. To further understand the mechanisms through which Lactobacillus protected chickens from Salmonella infection, the present study has investigated the Lactobacillus isolate(s)-induced host immune response of chickens to Salmonella enterica serovar Typhimurium infection. A thorough examination of cytokine gene expression in the ileum, caecal tonsils, and spleen on days 1 and 3 post-Salmonella infection showed a dynamic spatial and temporal response to Salmonella infection and Lactobacillus treatments. In most instances, it was evident that treatment of chickens with Lactobacillus isolates could significantly attenuate Salmonella-induced changes in the gene expression profile. These included the genes encoding pro-inflammatory cytokines [lipopolysaccharide-induced TNF factor, interleukin (IL)-6, and IL-8], T helper 1 cytokines [IL-12 and interferon (IFN)-γ], and T helper 2 cytokines (IL-4 and IL-10). Another important observation from the present investigation was that the response induced by a combination of Lactobacillus isolates was generally more effective than that induced by a single Lactobacillus isolate. Our results show that administration of certain selected Lactobacillus isolates can effectively modulate Salmonella-induced cytokine gene expression, and thus help reduce Salmonella infection in chickens.

Survey indicates circulation of 4/91 and QX-type infectious bronchitis viruses in Hungary in 2014 - Short communication.

Understanding the epidemiology and improving vaccinal protection against the highly variable chicken infectious bronchitis virus (IBV) requires the knowledge of circulating IBV serotypes/genotypes in defined geographic areas. Accordingly, the authors initiated a survey among the major poultry producers in Hungary in order to reveal the prevailing IBV serotypes in the country. Tracheal swabs and organ samples (caecal tonsils, kidneys, and trachea) were collected from broiler, layer, and meat-type breeder flocks, and were subjected to IBV detection by virus isolation and polymerase chain reaction (PCR). The IBV-positive samples were further characterised by nucleotide sequencing and phylogenetic analysis of a portion of the S1 IBV gene. Seventeen out of the 26 submitted samples proved to be positive for IBV. Sequence analyses revealed ten 4/91 and six QX serotypes, and a single D274 type IB virus. One sample contained a mixture of QX and Massachusetts serotype viruses. Presumably most of the 4/91 and D274 type viruses were vaccine strains. The proportion of QX type viruses and their observed variation are in good agreement with the situation in a few other European countries. The detected viruses clustered largely according to their geographic origin, with a few exceptions. If updated regularly, the preliminary 'virus map' will be useful for the adjustment of vaccination protocols.

The influence of dietary zinc source and coccidial vaccine exposure on intracellular zinc homeostasis and immune status in broiler chickens.

Coccidia are protozoal parasites which compromise mucosal integrity of the intestine, potentiating poultry morbidity. The host's Zn status influences the course of infection. Therefore, two experiments were designed to determine how supplemental Zn regimens impacted jejunal and caecal immune status and Zn transporter expression. Coccivac®-B was administered weekly at ten times the recommended dose as a mild coccidial challenge (10 CV). Zn was provided through a basal diet, supplemental zinc sulfate (ZnSO4), or a supplemental 1:1 blend of ZnSO4 and Availa®-Zn (Blend). Mucosal jejunum (Expt 1) and caecal tonsils (Expt 2) were evaluated for intracellular Zn concentrations and phagocytic capacity. Messenger expression of Zn transporters ZnT5, ZnT7, Zip9 and Zip13 were investigated to determine Zn trafficking. With 10 CV, phagocytic capacity was decreased in jejunal cells by 2%. In the caecal tonsils, however, phagocytic capacity increased with challenge, with the magnitude of increase being more pronounced with higher dietary Zn (10 CV × Zn interaction; P = 0.04). Intracellular Zn within caecal tonsils was found significantly reduced with 10 CV (27%, P = 0.0001). 10 CV also resulted in an overall increase in the ratio of Zip:ZnT transporters. With the exception of Zip13 transporter expression, dietary Zn source had little impact on any of the measured cellular parameters. Thus, intestinal mucosal tissues had reductions in intracellular free Zn during coccidial challenge, which was coupled with an upregulation of measured Zip transporters. This suggests that under coccidial challenge, intestinal cells attempt to compensate for the drop in intracellular Zn.

Immunomodulatory activity and control of Salmonella Enteritidis colonization in the intestinal tract of chickens by Lactobacillus based probiotic

Lactobacillus-based probiotics (LBP) are used as competitive exclusion to control pathogenic enterobacterial infections and improve the weight gain in broiler chickens. This study assessed the inhibition of Salmonella Enteritidis (SE) infection in one-week-old broiler chicks, using an experimental LBP containing four Lactobacillus strains isolated from chickens (L. acidophilus, L. fermentum, L. reuteri, L. salivarius). The immunomodulatory effects of this treatment were evaluated, through the analysis of cytokines and influx of macrophages, γδ, CD4+ and CD8+ T cells in the gut. The intestinal colonization by SE was reduced by 1.8CFU/g (log10) in chicks treated with LBP (p<0.05). The levels of pro-inflammatory cytokines (IL-1β, LITAF) were significantly reduced in treated chicks (p<0.05), whilst untreated chicks showed elevated inflammatory stimulus and an increased population of CD8+ T cells in the intestinal mucosa after challenge (p<0.05). Additionally, the LBP stimulated TLR2 expression in caecal tonsils. The adjuvant property of the Lactobacillus cell wall (LCW) was evaluated, demonstrating good capability to stimulate T helper 2 (Th2) cell proliferation. Pretreatment of chicks with LBP decreased the intestinal colonization by SE, minimizing the tissue lesions and inflammation after challenge and showed a potential use as adjuvant with injectable killed vaccines.

Age-related development and tissue distribution of T cell markers (CD4 and CD8a) in Chinese goose

Aquatic birds play n critical role in the transmission and dissemination of many important pathogens such as avian influenza virus. The cell-mediated immunity is very important in eliminating the intracellular antigens. Expression of CD4 and CD8 on T cell surface is essential for cell-mediated immune defence and T-cell development. However, the ontogeny of T lymphocytes in waterfowl is scarce and fragmentary. To address these questions, here we report the development and tissues distribution of CD4 and CD8α in goose embryo, gosling and goose by immunocytochemistry assay using monoclonal antibodies. Moreover, the age-related mRNA level of goose CD4 and CD8α in different immune tissues were study by real time quantitative PCR. Our results suggested that the high expression of CD4 and CD8α were readily found in thymus, which peaked at the first week post-hatch. And the highest expression level of CD4 and CD8α were detected in bursa of Fabricius, caecal tonsils, spleen and intestine at the second week, after that the expression level were gradually decreased. Interestingly, the remarkably high expression of CD4 and CD8α in Harderian gland were detected at the first week, which is about hundreds times more than that in other tissues. Our findings demonstrated that the development and the distribution of CD4 and CD8α are partly changed in an age-related way. Moreover, the histological morphogenesis of immune tissues were also discussed. Our results may shed lights on the better understand of T-cell mediate immunity in goose.

Histological and Ultrastructural Studies of Caecal Tonsil in Chicken (Gallus Domesticus)

Light and electron microscopic studies on caecal tonsil were done in layer chicken of various age groups ranging from day-old to forty weeks. The caecal tonsil revealed two types of lymphoid aggregations (germinal centre). The first type had an incomplete capsule and the second type was found encapsulated with connective tissue. The capsule of the germinal centre consisted of many layers of flattened reticular cells separated with an intercellular substance. The germinal centre consisted of lymphoblasts, lymphocytes of various sizes, reticular cells, plasma cells, mast cells and macrophages. In forty week-old birds, the lymphocytic population was observed to be comparatively reduced and more number of fibroblasts and collagen fibres were noticed. The caecal tonsil also had M cells with short and irregular microvillus.

Effects of Diatomaceous earth in amelioration of Aflatoxin induced patho-morphological changes in broilers

The ability of Diatomaceous earth (DAE) in reducing the detrimental effects of aflatoxin (AF) in broiler diet was evaluated. DAE was supplemented @ 400 and 800 mg Kg−1 of feed along with 0.5 and 1 ppm of AF Kg−1 of feed. A total of 360 healthy day old broiler chicks were divided into 9 groups comprising of control and treatment groups. Feeding of AF caused increased relative weight of liver, kidneys, heart and pancreas compared to the control group. However, the relative weight of thymus, spleen and bursa of Fabricius decreased in the aflatoxin fed birds. The prominent gross lesions were enlargement, yellowish discoloration, friable texture, varying degree of congestion in liver and kidneys. The lymphoid organs revealed reduction in size of the thymus, spleen and bursa of Fabricius. Histopathologically, liver revealed congestion, cellular swelling and fatty changes, degeneration and necrosis of hepatocytes, periportal and perivascular infiltration of mononuclear cells and connective tissue proliferation. Kidneys revealed mild to moderate degree of congestion and haemorrhages, tubular epithelial degeneration and infiltration of mononuclear cells along with heterophils. Lymphocytolysis and depletion of lymphoid cells were seen in thymus, spleen, bursa of Fabricius and caecal tonsils. Intestines showed degeneration and necrosis of villus epithelium.

Cytokine gene expression profiles in chicken spleen and intestinal tissues during Ascaridia galli infection

In the poultry production industry, chickens with access to outdoor areas are exposed to a wide range of parasites e.g. the helminth Ascaridia galli. By real-time quantitative RT-PCR, the relative gene expression of the T helper 1 (Th1) cytokine IFN-γ, the T helper 2 (Th2) cytokine IL-13, the anti-inflammatory cytokines IL-10 and TGF-β4 and the pro-inflammatory cytokine IL-17F were determined over a period of 3 weeks in A. galli and non-A. galli-infected chickens. A characteristic Th2 response was observed in the jejunum of A. galli-infected chickens with increased expression of IL-13 and decreased expression of IFN-γ from day 14 post infection. At the putative time of larvae invasion into the intestinal mucosa (day 7), an increased expression of IFN-γ, IL-10, and TGF-β4 was observed in the spleen. At the putative onset of the innate immune response (day 10), a decreased expression of jejunal IFN-γ and IL-13 was observed. Finally, at the expected period of an adaptive immune response (days 14–21) a general decreased expression of IFN-γ and TGF-β4 in spleen and IFN-γ in jejunum was followed by a decreased expression of IFN-γ and IL-10 at day 21 in caecal tonsils.

Pathomorphological studies of polyserositis in commercial caged layer chicken

ObjectiveTo detect etiological agents and pathological changes associated with polyserositis in commercial layer chicken. MethodsTen commercial layer flocks which had a sudden increase in mortality and a drop in egg production with lesions suggestive of colisepticemia were investigated. Flock details and pathological changes were recorded in affected flocks to assess the prevalence and impact of polyserositis on commercial layer chicken. Trachea, heart blood, liver, oviduct, cloacal swab, poultry house environment samples, water and feed samples were screened for bacteriological agents. Pooled tissue (trachea, lung, spleen, caecal tonsil, kidney and oviduct) samples from colisepticemia cases were screened for viral agents. Serum samples collected from affected flocks were screened for Newcastle disease virus, infectious bronchitis virus and egg drop syndrome-76 virus by haemagglutination inhibition test, and for Mycoplasma gallisepticum and Mycoplasma synoviae by enzyme linked immunosorbent assay. ResultsOn necropsy examination of dead birds, fibrinous polyserositis and congestion of various visceral organs were noticed. Microscopically, deciliation and hypertrophy of mucus glands showed in the tracheal epithelium. Vascular derangements and infiltration of inflammatory cells showed in the lungs and air sac. Fibrinous polyserositis, focal necrosis and infiltration of inflammatory cells showed in parenchyma of heart and liver. Inflammatory changes were observed in the ovary and oviduct. Escherichia coli (E. coli) was isolated as a pure culture from 108 birds and from the poultry house environment of the ten affected flocks. Among the eight E. coli serotypes, identified serotypes O78 and O111 were predominant. In colisepticemia affected flocks egg production drop and mortality varied from 3%-10% and 2%-5%, respectively and occured during the peak egg production (21 to 40 weeks) and southwest monsoon season (June to September). ConclusionsThe present study revealed that the colisepticemia inducing E. coli isolates were derived from the layer house environment. Hence, the incidences of colisepticemia can be minimized by effectively reducing the bacterial load in the layer house environment through appropriate biosecurity measures.