Chicken Thymus Research Articles

Ammonia Exposure-Induced Immunological Damage in Chicken Lymphoid Organs via TLR-7/MYD88/NF-κB Signaling Pathway and NLRP3 Inflammasome Activation.

Ammonia (NH3) is a hazardous gas that pollutes the environment and causes irritation. Its harmful effects on chickens, including its impact on their immune system, have previously been observed. However, the mechanism by which NH3 exposure causes immune system disorders in chickens remains unclear. The bursa of Fabricius (BF) and thymus are the two main lymphoid organs responsible for the proliferation, differentiation, and selection of B- and T-lymphocytes, both critical for the innate immune response of the host. In this study, we investigated the mechanism of NH3-induced immune dysregulation in broiler chickens. Transmission electron microscopy (TEM) revealed swollen mitochondria and breakage of the large crista lining, membrane deformation, chromatin condensation, increased vacuolation, and blood vessel spasms in the NH3-exposed BF and thymus tissues. Immunofluorescent analysis showed clustering of CD4+ and CD8+ cells, indicating an active immune response to NH3 exposure. Furthermore, NH3 exposure enhanced the mRNA expressions of Toll-like receptor 7 (TLR-7), myeloid differentiation primary response 88 (MYD88), and nuclear factor-kappa B (NF-κB), along with their proteins, and led to activation of the TLR-7/MyD88/NF-κB signaling pathway and NLRP3 inflammasome in chicken thymus tissues. Both mRNA and protein levels of key inflammation-related genes and proteins were upregulated in the NH3-treated group, highlighting a robust inflammatory response due to NH3 exposure. The specific findings of significant structural damage to key lymphoid organs and activation of inflammatory pathways in broiler chickens upon NH3 exposure can provide guidance for future, targeted therapies to improve poultry health.

In ovo betaine and heat acclimation affect hatching results, growth performance and immunity of the broilers under cyclicheatstress.

This study investigated the effects of in ovo betaine and thermal manipulation during incubation on growth performance, and some immune parameters of broilers under cyclic heat stress (CHS). Eggs were divided into 5 groups and incubated at 1) 37.8°C and 60% relative humidity (Control incubation and not-injected, CI); 2) eggs were incubated at CI and in ovo betaine injected into yolk sac on d 11 (E11) (CI + In ovo); 3) eggs were exposed to 38.8°C for 8h between 10 and 18d of incubation (heat acclimation, HA); 4) eggs were incubated at HA and in ovo betaine applied (HA + In ovo); 5) positive control: eggs were incubated at CI and injected with saline. Hatched chicks were raised under standard management conditions until 21 d, between 21 and 42 d half of the chickens in each incubation treatment were kept either at optimum (OPT) or at CHS. In ovo and HA did not affect hatching performance. In ovo increased thymus and spleen weights of chicks. Serum IgG was higher in HA + In ovo chicks. From d 7 to 21, in ovo chicks were heavier body weights, consumed more feed, and better feed conversion than those from CI. The body weights of HA chickens were similar in OPT and CHS on d 28 and 35. CHS reduced the body weight of CI chickens which was compatible with their feed consumption. Moreover, feed intake of HA + In ovo chickens exposed to CHS was higher than those not injected indicating that HA + In ovo enhanced thermoregulation of chickens under CHS.

Effects of Heat-Induced Oxidative Stress and Astaxanthin on the NF-kB, NFE2L2 and PPARα Transcription Factors and Cytoprotective Capacity in the Thymus of Broilers.

The thymus, a central lymphoid organ in animals, serves as the site for T cell development, differentiation and maturation, vital to adaptive immunity. The thymus is critical for maintaining tissue homeostasis to protect against tumors and tissue damage. An overactive or prolonged immune response can lead to oxidative stress from increased production of reactive oxygen species. Heat stress induces oxidative stress and overwhelms the natural antioxidant defense mechanisms. This study's objectives were to investigate the protective properties of astaxanthin against heat-induced oxidative stress and apoptosis in the chicken thymus, by comparing the growth performance and gene signaling pathways among three groups: thermal neutral, heat stress, and heat stress with astaxanthin. The thermal neutral temperature was 21-22 °C, and the heat stress temperature was 32-35 °C. Both heat stress groups experienced reduced growth performance, while the astaxanthin-treated group showed a slightly lesser decline. The inflammatory response and antioxidant defense system were activated by the upregulation of the NF-kB, NFE2L2, PPARα, cytoprotective capacity, and apoptotic gene pathways during heat stress compared to the thermal neutral group. However, expression levels showed no significant differences between the thermal neutral and heat stress with antioxidant groups, suggesting that astaxanthin may mitigate inflammation and oxidative stress damage.

Very virulent infectious bursal disease virus infection triggered microscopic changes, apoptosis, and inflammatory cytokines imbalance in chicken spleen and thymus

ABSTRACT Infectious bursal disease virus (IBDV) can cause a highly contagious disease, resulting in severe damage to the immune system that causes immunosuppression in young chickens. Both spleen and thymus are important immune organs, which play a key role in eliciting protective immune responses. However, the effects of very virulent IBDV (vvIBDV) strain LJ-5 infection on chicken spleen and thymus are still unknown. In the present study, 3-week-old specific pathogen-free chickens were infected with vvIBDV for 1–5 days. The vvIBDV infection significantly increased the spleen index and decreased the thymus index. Microscopic analysis indicated necrosis, depletion of the lymphoid cells, and complete loss of structural integrity in spleen and thymus. Ultrastructural analysis displayed mitochondrial and nuclear damage, including mitochondrial cristae breaks, and deformation of nuclear membrane in vvIBDV-infected spleen and thymus tissues. Cytokine levels increased in the spleen and thymus after IBDV infection, promoting inflammation and causing an inflammatory imbalance. Moreover, the mRNA expression of apoptosis-related genes was significantly upregulated in the vvIBDV-infected group compared to the control group. Meanwhile, the mRNA expression of mitochondrial dynamics was altered in the spleen and thymus of vvIBDV-infected chickens. These results suggested that vvIBDV infection triggers an imbalance of inflammatory cytokines, and apoptosis in the spleen and thymus, resulting in immune injury in chickens. This study provides basic data for the further study of vvIBDV pathogenesis.

Morphological features of the poultry thymus

This article reviews the literature on the morphological features of the poultry thymus. Since the preservation of livestock and disease prevention is a constant problem, the issue of poultry care will always remain in the forefront. Efforts to preserve the population and increase their productivity are directly related to strengthening poultry immunity and the state of their immune system. The study of the morphology of immune system organs allows us to objectively assess the effectiveness of methods for the prevention and treatment of various diseases, as well as to identify critical periods of development of the immune system and the body as a whole. When assessing the immune status of poultry, much attention is paid to the state of lymphoid organs, including the thymus. Currently, aspects related to the dynamics of development of immunocompetent organs during the postnatal period of ontogenesis and the time frame of their involution remain unresolved. Understanding the morphological features of the thymus and its changes is a key element in assessing the function of the immune system. It was found that with the growth and development of chicks, the absolute and relative weight of the thymus increases. However, at the onset of reproductive maturity, these values decrease significantly. Involution of the thymus mass occurs, the boundary between cortical and cerebral substances becomes less distinct, and the cellular composition of the thymus changes. The process of age-related involution is accompanied by a decrease in lymphoid tissue and T-lymphocytes. It is worth noting that the total number of circulating T-lymphocytes remains stable, as this population includes long-lived cells that do not require constant renewal. In this context, there is a change in the ratio of cortical and cerebral substances, the growth of connective tissue stroma and adipose tissue. It is noted that stress factors are one of the causes of early thymic involution, and the degree of development and morphological state of the thymus significantly affect the body's resistance to infections. Changes in the structure and morphometry of the chicken thymus can be an important criterion for the morphological diagnosis of immunodeficiencies in poultry.

RNA-seq reveals role of cell-cycle regulating genes in the pathogenicity of a field very virulent infectious bursal disease virus.

Infectious bursal disease virus (IBDV) infection causes highly contagious and immunosuppressive disease in poultry. The thymus, serving as the primary organ for T cell maturation and differentiation, plays an important role in the pathogenicity of IBDV in the infected chickens. However, there are no reports on the molecular pathogenesis of IBDV in the thymus currently. The aim of the study was to elucidate the molecular mechanisms underlying the pathogenicity of a field very virulent (vv) IBDV strain NN1172 in the thymus of SPF chickens using integrative transcriptomic and proteomic analyses. Our results showed that a total of 4,972 Differentially expressed genes (DEGs) in the thymus of NN1172-infected chickens by transcriptomic analysis, with 2,796 up-regulated and 2,176 down-regulated. Meanwhile, the proteomic analysis identified 726 differentially expressed proteins (DEPs) in the infected thymus, with 289 up-regulated and 437 down-regulated. Overall, a total of 359 genes exhibited differentially expression at both mRNA and protein levels, with 134 consistently up-regulated and 198 genes consistently down-regulated, as confirmed through a comparison of the RNA-seq and the proteomic datasets. The gene ontology (GO) analysis unveiled the involvement of both DEGs and DEPs in diverse categories encompassing cellular components, biological processes, and molecular functions in the pathological changes in IBDV-infected thymus. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the host mainly displayed severely disruption of cell survival/repair, proliferation and metabolism pathway, meanwhile, the infection triggers antiviral immune activation with a potential emphasis on the MDA5 pathway. Network inference analysis identified seven core hub genes, which include CDK1, TYMS, MCM5, KIF11, CCNB2, MAD2L1, and MCM4. These genes are all associated with cell-cycle regulating pathway and are likely key mediators in the pathogenesis induced by NN1172 infection in the thymus. This study discovered dominant pathways and genes which enhanced our understanding of the molecular mechanisms underlying IBDV pathogenesis in the thymus.

Effect of Addition Sinbiotic Isolate Pediococcus pentosaceus Strain N6 and Cassava Peel on Immunity Organs and Total Microbes in the Small Intestine of Super Native Chicken

Factory feed is often added with antibiotics as a growth promoter. Giving synthetic antibiotics is very dangerous for health. This study aims to determine effect of addition synbiotic isolate Pediococcus pentosaceus strain N6 and cassava peel flour on the immune organs and total microbes in the small intestine of super native chickens. This research was conducted in Pancur Batu from September - December 2022. The design used was a completely randomized design (CRD) with 4 treatments 5 replicates so that 20 experimental units were obtained. The super native chicken used were 100 DOC. The treatments given were P0 (basal ration without sinbiotic), P1 (basal ration + sinbiotic 150 ml/kg ration), P2 (basal ration + sinbiotic 300 ml/kg ration), and P3 (basal ration + sinbiotic 450 ml/kg ration). Parameters studied were weight percentage of immune organs and total microbial colonies. The results of this study indicated that the addition of synbiotic isolate Pediococcus pentosaceus strain N6 and fermented cassava peel flour up to a dose of 450 ml/kg as an alternative feed for native chickens increased percentage weight of spleen, thymus, bursa fabrisius, and total microbial colony of super native chickens.

The signal pathway of melatonin mediates the monochromatic light-induced T-lymphocyte apoptosis in chicken thymus

Our previous study revealed that under monochromatic red light (RL), the melatonin nuclear receptor reduces the proliferation activity of broiler thymic lymphocytes through the P65 signaling pathway. The main objective of this study was to investigate the signal mechanism by which RL decreases thymic lymphocyte proliferation. Initially, broilers were purchased and randomly assigned to be fed under white light (WL), red light (RL), green light (GL), and blue light (BL). Pinealectomy was performed 3 d later, and the broilers were euthanized after 14 d. The results showed that the expression of the antiapoptotic proteins Bcl-2/Bcl-xl decreased under RL, while the expression of the pro-apoptotic factor Bax/caspase-3 and the pro-inflammatory factors INF-γ/TNF-α/IL-6 increased. After pinealectomy, the expression of Bax/TNF-α/IL-6 increased in conjunction with the decrease in Bcl-2 expression. In vitro experiments demonstrated that exogenous melatonin decreased the expression of Bax/TNF-α/IL-6 in thymic lymphocytes of chicks reared under RL. This melatonin-induced effect was enhanced by SR1078 (RORα/RORγ agonist) but attenuated by SR3335 (RORα antagonist) and BAY (P65 antagonist). These findings revealed that the melatonin nuclear receptor RORα/RORγ promotes the expression of the pro-apoptotic factor Bax/caspase-3 and the pro-inflammatory factors INF-γ/TNF-α/IL-6, while inhibiting the expression of the antiapoptotic factor Bcl-2/Bcl-xl. Our research suggested the signaling pathway of monochromatic red light impacts the apoptosis of thymus lymphocytes in broiler.

Cadmium acetate induced immunotoxico and histopathological modulations in thymus of Kuroiler chicks

Cadmium acetate induced immunotoxico and histopathological modulations in thymus of Kuroiler chicks

Etlik Piliçlerde Sıcak İklimde Soğuk Su ve Yerleşim Sıklığının Oksidatif Metabolizmaya Etkisi

The present experiment was conducted to investigate the effect of drinking water temperature and stocking density (SD) on oxidative metabolism in the heart, liver, bursa fabricius, and thymus in broiler chickens raised under heat stress. The experiment comprised of 360 one-day-old Ross 308 male broiler chickens randomly divided to 6 experimental groups with 4 replicates in each group. Experimental treatments included three different SD (low = 12 birds/m2, medium = 15 birds/m2 or high = 18 birds/m2) and two different drinking water temperature (10oC or 31oC) in a 3 x 2 factorial arrangement. At the end of the experiment (42 days of age), two birds per replicate were euthanized for sample collection. The results indicated high SD increased oxidative damage and caused an increase in MDA formation in the heart, liver and thymus. On the other hand, cold water ameliorated the oxidative damage due to the high SD in the thymus. In the study, the statistically non-significant interaction was generally determined between cage stocking density and cold drinking water on the antioxidant system. Besides, while cold water administration increased CAT activity in heart and thymus tissues, decreased GSH activity. In conclusion, drinking water temperature and stocking density are key environmental factors effecting oxidative metabolism when broilers under high temperature conditions; however, more studies are needed in terms of the interactive effects of water temperature and stocking density on antioxidant enzymes under current conditions.

Histomorphological changes in the organs of the immune system of broiler chickens when using drug Betulin

Currently, much attention is paid to maintaining the health of poultry and in this regard, the role of the immune system can hardly be overestimated. Specific protective reactions are carried out by immunocompetent cells that are located in the central and peripheral organs of the immune system. The purpose of the research was to study histomorphological changes in the thymus and Bursa fabricii of broiler chickens when using the phytodrug Betulin. The histomorphological changes in the central organs of the immune system (thymus and fabricius sac) of broiler chickens when using Betulin have been presented in the article. Betulin is a natural pentacyclic triterpenoid of the lupan series. It is found in a large number of plants (hazel, calendula, licorice), but it does not occur in free form. On an industrial scale, it is extracted from birch bark – the outer layer of the bark of white birch (Betula alba), hanging (Betula pendula). Its biological activity has been confirmed in the course of scientific research in more than forty international scientific centers. The effectiveness of using triterpene compounds as direct regulators of the activity of the body’s enzymatic systems has been demonstrated. The research was carried out in the veterinary department of poultry at Siberian Scientifi c and Research Institute of Poultry – a branch of the Federal State Budget Scientific Institution “Omsk Agrarian Scientific Center” on broiler chickens of the cross Sibiryak. The chickens of the experimental groups were used Betulin from 7–21 days, the 1st experimental group at a dose of 2,5 mg/kg of live weight, the 2nd – 5,0 mg/kg, the 3rd – 10,0 mg/kg and the 4th – 15,0 mg/kg of live weight. The poultry of the control group did not receive the phytodrug Betulin. Vaccination of chickens was carried out at the age of 7 days against Newcastle disease viruses and infectious bronchitis of chickens, at 14 days against infectious bursal disease. It was found on the base histological studies that Betulin in doses of 10,0 and 15,0 mg/kg of live weight stimulated the proliferation of lymphocytes and differentiation of the central organs of the immune system of broiler chickens.

In ovo given sunset yellow adversely affects embryonic development of chick thymus and bursa Fabricii as evidenced by histological and enzyme histochemical findings

BackgroundSunset yellow (E110) has largely been used as food coloring agent. Complaints accumulated on E110 for possible detrimental effects on the immune functions such as allergenicity in the children. In this study, the effects of different doses of E110 on embryonic development of chicken primary lymphoid organs, thymus and bursa of Fabricius were determined by means of histological, histomorphometrical and histochemical methods. A total of 250 fertilized eggs from the Ross 508 line were used in the study. The eggs were divided into 5 groups as non-treated, sham-exposed and 100 ng/egg, 500 ng/egg, 1000 ng/egg E110-injected groups, each having 50 eggs.ResultsIn the 1.000 ng/egg E110-administered group, embryonic development of chicken thymus and bursa of Fabricius were retarded.ConclusionsE110 given in ovo before incubation retarded the embryonic development of the avian thymus and bursa of Fabricii. The effect is more pronounced in the 1.000 ng/egg group.

Polystyrene microplastics mediate inflammatory responses in the chicken thymus by Nrf2/NF-κB pathway and trigger autophagy and apoptosis

Microplastics (MPs) are a hot environmental contaminant now. However, researchers paid little attention to their effects on immune organs such as the thymus. Here, we exposed chickens to a concentration gradient of polystyrene microplastics (PS-MPs) and then followed the decrease in the thymus index. HE staining showed cellular infiltration in the thymus. The assay kit corroborated that PS-MPs impelled oxidative stress in the thymus: increased MDA levels, downregulated antioxidants such as SOD, CAT, and GSH, and significantly undermined total antioxidant capacity. Western blotting and qRT-PCR results showed that Nrf2/NF-κB, Bcl-2/Bax, and AKT signaling pathways were activated in the thymus after exposure to PS-MPs. It stimulated the increased expression of downstream such as IL-1β, caspase-3, and Beclin1, triggering thymus inflammation, apoptosis, and autophagy. This study provides new insights into the field of microplastic immunotoxicity and highlights potential environmental hazards in poultry farming.

MDV-induced differential microRNA expression in the primary lymphoid organ of thymus.

Marek's disease virus (MDV), a highly contagious cell associated virus, is the etiological agent of Marek's disease (MD), a lymphoproliferative and neuropathic disease of domestic chickens. Clinical signs of MD include transient paralysis, bursal/thymic atrophy, and T cell lymphomas. MicroRNAs (miRNAs) are short single-stranded non-coding RNAs that regulate gene expression by transcriptional suppression or mRNA degradation. Herpesviruses, including MDV, encode for miRNAs that are known to play essential roles in viral pathogenicity, oncogenesis, and evasion of immune responses. In this study, we performed miRNA sequencing in thymuses of control and MDV-infected chickens of MD-resistant (63) and susceptible (72) lines at 21 days post infection (dpi). The thymus is a lymphoid organ that undergoes severe atrophy due to MDV-induced apoptotic mediated destruction of T cells. Sequence analysis identified 658 total chicken miRNAs in the thymuses of control and MDV-infected birds of both lines. Of these, 453 were novel and 205 were known microRNAs. All novel miRNAs mapped to chicken genome with no sequence homology to existing miRNAs in the chicken miRbase. Comparative analysis between the thymuses of control and infected birds of resistant and susceptible lines identified 78 differentially expressed microRNAs that might provide insights into mechanisms of thymus atrophy.

Residue of thiram in food, suppresses immune system stress signals and disturbs sphingolipid metabolism in chickens

Thiram, a well-known sulfur containing organic compound is frequently and extensively used in agriculture because of high biological activity to control different pests. In certain cases, due to long persistence in the environment pesticides and other environmental contaminants induce undesirable toxic impacts to public health and environment. To ascertain the potential mechanisms of toxicity of thiram on different immune organs of broilers, a total of 100 one-day-old chicks were obtained and randomly divided into two groups including thiram group (50 mg/kg) and untreated control group. Thymus and spleen tissues were collected at the age of 14 days from the experimental birds. At necropsy level, thymus was congested, enlarged and hyperemic while spleen had no obvious lesions. The results on mechanisms (apoptosis and autophagy) of immunotoxicity showed significantly increased expression of bax, caspase3, cytc, ATG5, beclin1 and p62 in spleen of treated mice. Results indicated significantly decreased expression of m-TOR and bcl2 to activate apoptosis and autophagy. The expressions of bax, p53 and m-TOR were up-regulated in the thymus while the expressions of ATG5 and Beclin1 were down-regulated to mediate cell apoptosis and inhibit autophagy. The results on different metabolome investigation showed that the sphingolipid metabolism in the thymus of chicks exposed to thiram was disrupted resulting in up-regulation of metabolites related to cell membrane components such as SM, galactosylceramide and lactosylceramide. The results of our experimental research suggest that thiram can interfere with the sphingolipid metabolism in thymus and angiogenesis, inhibit the proliferation of vascular endothelial cells to induce potential toxic effects in chicken.

Evaluation of the effect of antibacterial and probiotic drugs on morphological changes in the body of broiler chickens

The results of a comparative histological study of the morphological reaction of parenchymal organs and organs of the immune system in broiler chickens using antibiotics and probiotics showed a positive effect of the probiotic drug on the body of broiler chickens of the experimental group. Two groups were formed according to the principle of analogues, a control and an experimental group of 35 heads each. Chickens of the control and experimental groups received the antibiotic enrofloxacin twice for 3 days up to 14 days of age according to the scheme of prevention of infectious diseases. Chickens of the experimental group received a feed additive (probiotic) based on microorganisms Bifidobacterium animalis from day 15 to 30. In a comparative study of the thymus of broiler chickens of the experimental group, the predominance of the cortical substance over the cerebral substance was noted in most of the lobules located on the periphery, and only in the merged lobules of the middle part of the thymus, the brain zone with a significant number of Ghassal bodies prevailed, a pseudoeosinophilic reaction was noted in the brain zone of the experimental chickens, as a result of the utilization of deposits and purification of the organ from the cells of the dead by the type of apoptosis. Histological studies of the spleen revealed activation of lymphoid follicles: in the chickens of the control group they were single on the preparation, and in the chickens of the experimental group there were three or more of them in one field of view. This indicates the activation of humoral immunity in chickens of the experimental group.In the study of the pancreas in chickens of the experimental group, a positive tendency was noted to increase the number and size of the islets of Langerhans, which regulate the function of carbohydrate metabolism.Analysis of the results of a comparative histological study of the morphological reaction of parenchymal organs and organs of the immune system showed that a number of reversible and irreversible pathological changes in organs were noted in the control group. Whereas in the experimental group where the probiotic was used, the organs corresponded to the physiological norm, which indicates a positive effect on the organs and on the body as a whole.

Effect of Adding Cassava Peel and Lactic Acid Bacteria as a Feed Additive to the Weight of Immune Organs of Super Native Chicken

This study aims to evaluate the use of cassava peels added with lactic acid bacteria on the immune organ weight of super native chickens. The material used in this study was 144 Day Old Chick (DOC) super unsex native chicken with an average body weight of 34 ± 3,14 gram. The research design used was a completely randomized design (CRD) with a dose of liquid feed additive in the form of a combination of cassava peel flour and lactic acid bacteria mixed with rations. The treatments in this study included T0: basal ration, T1 (basal ration + 10% feed additive ml/kg), T2 (basal ration + 15% feed additive ml/kg) and T3 (basal ration + 20% feed additive ml/kg). The parameters observed were body weight, the relative weight of lymph, thymus, and bursa Fabricius superficial chicken stock exchange. The result showed that the combination of cassava peel and lactic acid bacteria had no significant effect (P>0.05) on body weight, the relative weight of the lymph organs, thymus, and bursa Fabricius of super native chickens. This research concludes that the combination of cassava peel and lactic acid bacteria as a feed additive can maintain chickens' health by not increasing the relative weight of the super native chicken immune organs to the level of 200 ml/kg.

Deletion of the Viral Thymidine Kinase in a Meq-Deleted Recombinant Marek's Disease Virus Reduces Lymphoid Atrophy but Is Less Protective.

Marek’s disease (MD) is a ubiquitous disease of domesticated chickens and its etiologic agent is the Gallid alphaherpesvirus 2 (GaHV-2), also known as Marek’s disease virus (MDV). MD is currently controlled by vaccination using live attenuated strains of MDV (e.g., CVI988/Rispens), non-pathogenic serotypes of MDV (GaHV-3), or non-pathogenic strains of the related Melagrid alphaherpesvirus 1 (MeHV-1). One attractive strategy for the production of new vaccine strains is a recombinant MDV attenuated by the deletion of the major viral oncogene meq. However, meq-deleted variants of MDV cause atrophy of the bursa and thymus in maternal antibody-negative chickens, and the resulting immunosuppression makes them unsuitable. Herein we detail our attempt to mitigate the lymphoid atrophy caused by meq-deleted MDV by further attenuation of the virus through ablation of the viral thymidine kinase (tk) gene. We demonstrate that ablation of the viral tk from the meq-deleted virus rMd5B40/Δmeq resulted in a virus attenuated for replication in vitro and which spared chickens from atrophy of the lymphoid organs in vivo. When the rMd5B40/Δmeq/Δtk/GFP was used as a vaccine it was protective against challenge with the vv+MDV strain 686, but the protection was less than that provided by the CVI988/Rispens vaccine.

Quercetin ameliorates ochratoxin A-Induced immunotoxicity in broiler chickens by modulation of PI3K/AKT pathway

Ochratoxin A (OTA) is a fungal secondary metabolite produced by certain species of Aspergillus and Penicillium, and exerts immunosuppressive effect on humans and animals. Quercetin (QUE) is one of the flavonoids produced as a plant-secondary metabolite. The present study was designed to evaluate the efficacy of QUE against the immunotoxic hazard of OTA in broiler chickens. Forty one-day-old broiler chicks were randomly and equally allocated into four groups; control, OTA (0.5 mg/kg feed), QUE (0.5 g/kg feed) and OTA + QUE (0.5 mg/kg OTA + 0.5 g/kg QUE). The results revealed that dietary OTA induced a significant decrease in the antibody response to Newcastle Disease (ND), Infectious Bronchitis (IB) and Avian Influenza (AI) vaccination and in the lymphoproliferative response to Phytohemagglutinin-P (PHA-P). Ochratoxin A also induced oxidative stress and lipid peroxidation in the bursa of Fabricius, spleen and thymus tissues of chickens as demonstrated by decreased CAT and GSH levels and increased TBARS content. In addition, administration of OTA resulted in apoptosis, which was evident by the increased expression level of PTEN, Bax and Caspase-3 genes and decreased expression level of PI3K, AKT and Bcl-2 genes. Furthermore, exposure to OTA resulted in various pathological lesions in the bursa of Fabricius, spleen and thymus of chickens. On the other hand, administration of QUE ameliorated most of the immunotoxic effects of OTAby its immunomodulatory, antioxidant and anti-apoptotic activities. Taken together, the results suggested that QUE potentially alleviated the OTA-induced immunotoxicity in broiler chickens, probably through amelioration of oxidative stress and activation of the PI3K/AKT signaling pathway.

Dietary genistein supplementation alters mRNA expression profile and alternative splicing signature in the thymus of chicks with lipopolysaccharide challenge

Genistein is abundant in the soybean products, which exerts prominent effects on immune function. Little information is available about the effect of dietary genistein on thymic transcriptome, especially when suffering from lipopolysaccharide challenge. In this study, 180 one-day-old male broilers were randomly allocated to 3 groups: nonchallenged chicks given a basal diet (CON), and lipopolysaccharide-challenged chicks fed a basal diet (LPS), or lipopolysaccharide-challenged chicks fed a basal diet supplemented with 40 mg/kg genistein (GEN). Lipopolysaccharide injection induced thymocyte apoptosis and inflammatory reactions in the chicks. The results showed dietary genistein significantly reduced the percentage of CD3+ T lymphocytes by 10.04% and CD4+/CD8+ T lymphocyte ratio by 21.88% in the peripheral blood induced by lipopolysaccharide injection (P < 0.05). In addition, genistein significantly reduced the thymus index by 50% and apoptotic index by 12.34% induced by LPS challenge (P < 0.05). Transcriptomic analysis identified 1,926 DEGs (1,014 upregulated and 912 downregulated, P < 0.05) between GEN and LPS groups, which altered the mRNA expression profile and signaling pathways (Toll-like receptor, and NOD-like receptor signaling pathway) in the thymus. Furthermore, 5 splicing (AS) isoforms of the Drosophila Disabled-2 (DAB2) gene were detected, which were significantly upregulated in the GEN group compared with that in the LPS group. In summary, dietary genistein supplementation altered the RNA expression profile and AS signatures in the thymus, and alleviated immune response against lipopolysaccharide challenge.