Bursa Of Fabricius In Broilers Research Articles

RETRACTION: Transcriptome Analysis Reveals Potential Mechanisms of the Effects of Dietary Enteromorpha Polysaccharides on Bursa of Fabricius in Broilers.

RETRACTION: Transcriptome Analysis Reveals Potential Mechanisms of the Effects of Dietary Enteromorpha Polysaccharides on Bursa of Fabricius in Broilers.

MiR-144-3p targets STC1 to activate PI3K/AKT pathway to induce cell apoptosis and cell cycle arrest in selenium deficiency broilers

Selenium (Se) is an indispensable trace element in vertebrate. Se deficiency can damage the immune system. Studies have shown that Se deficiency can cause immune organ damage by regulating the expression of microRNA. Bursa of Fabricius is a special immune organ in poultry. In order to explore the mechanism of bursa of Fabricius injury caused by Se deficiency and the role of miRNA in this process. Firstly, we established the Se deficient model of broilers in vivo and found that Se deficiency could induce apoptosis and cell cycle arrest of bursa of Fabricius cells through Phosphoinositide 3-kinase (PI3K)/Protein Kinase B (AKT) pathway. Secondly, we inferred miRNA (miR-144-3p) and target gene Stanniocalcin 1 (STC1) that may regulate PI3K/AKT pathway through biological analysis system, and further predicted and determined the targeting relationship between them through dual luciferase, it was found that miR-144-3p was highly expressed in the process of cell apoptosis and cell cycle arrest induced by Se deficiency. Finally, in order to further understand whether miR-144-3p/STC1 axis is involved in the process, miR-144-3p knockdown and overexpression experiments were carried out, it was found that miR-144-3p inhibitor can reduce the occurrence of cell apoptosis and cell cycle arrest. In conclusion, Se deficiency can induce apoptosis and cell cycle arrest of bursa of Fabricius in Broilers by up regulating miR-144-3p targeting STC1 and activating PI3K/AKT pathway, leading to injury of bursa of Fabricius in broilers.

Chai Hu oral liquid enhances the immune functions of both spleen and bursa of Fabricius in heat-stressed broilers through strengthening TLR4-TBK1 signaling pathway

Heat stress can affect the poultry production and immune status of broilers. Heat stress disrupts intestinal integrity and increases intestinal inflammation, which is related with body immune dysfunction. Chai Hu oral liquid used as an antipyretic and anti-inflammatory drug is widely used in exogenous fever of poultry, but its resistance to heat stress and the mechanism is still unclear. In this study, a chronic heat stressed broilers model was established to explore the mechanisms of broilers’ immune function changes and the effects of Chai Hu oral liquid. In this study, a total of 480 broilers were randomly divided into 6 groups with 80 replicates. Heat stress (HS) group broilers were stressed at 35 ± 2°C for 5 or 10 consecutive d with 6 h/d. Heat stressed (for 5 or 10 d) broilers were given with Jieshu KangreSan (Positive), Chai Hu oral liquid high, middle and low dosage (CH-High, CH-Mid, CH-Low) by oral administration. Birds in control group were treated with the same volume of PBS only in 25 ± 2°C. All birds were sacrificed at last heat stress challenged day. Changes in immune function were assessed by immune organs index, serum IFN-γ level, gene and protein expressions of immune factors in spleen and bursa of Fabricius. Results from this experiment showed that heat stress enhanced the immune organs’ edema by directly increased the organs indexes of spleen and bursa of Fabricius in broilers. Heat stress for 10 d also increased bursa of Fabricius HSP70 protein level and significantly lowered the spleen and bursa of Fabricius proteins expressions of IFN-α, IFN-β, and IFN-γ in broilers. The IFN-β and IFN-γ protein levels in spleen and bursa of Fabricius also decreased in heat stressed broilers for 5 d. The gene and protein expressions of TLR4 and TBK1 markedly decreased in spleen and bursa of Fabricius of broilers treated with chronic heat stress. Chai Hu oral liquid reduced edema of immune organs and elevated TLR4-TBK1 signaling pathway to release immune factors. Above results indicated that chronic heat stress induced impaired immune function by inhibiting TLR4-TBK1 signaling pathway, and Chai Hu oral liquid had effective protection of body's immune ability by enhancing this signaling pathway.

Transcriptome analysis reveals potential mechanisms of the effects of dietary Enteromorpha polysaccharides on bursa of Fabricius in broilers.

The present study was conducted to evaluate the effects of dietary supplementation of Enteromorpha polysaccharides (EP) on relative organ weight of broilers, and RNA‐seq technique was used to reveal the potential molecular mechanisms of the positive effects of EP on relative organ weight. A total of 396 1‐day‐old male chicks (Arbor Acres) were randomly assigned to six dietary treatments containing EP at 0 (EP0), 1000 (EP1000), 2500 (EP2500), 4000 (EP4000), 5500 (EP5500), and 7000 (EP7000) mg/kg levels for a 35‐day feeding trial. At the end of feeding trail, six birds (one bird from each replicate cage) were randomly selected from each treatment and then slaughtered for relative organ weight analysis. The results showed that the relative weight of bursa of Fabricius were increased in the EP1000 group (p < 0.05), and then three bursa of Fabricius samples from each group (EP0 and EP1000) were randomly selected for RNA‐seq analysis. The results of RNA‐seq analysis showed that there were 20 differentially expressed genes (DEGs) between EP0 and EP1000 groups, among the DEGs, 6 genes were upregulated and 14 genes were downregulated by EP1000 supplementation (p‐adjust < 0.05). Gene ontology (GO) enrichment analysis suggested that the DEGs were mainly enriched in negative regulation of toll‐like receptor 9 signaling pathway (p‐corrected < 0.05). Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that the DEGs were mainly enriched in phagosome, mitophagy‐animal, Salmonella infection, autophagy‐animal signaling pathways (p‐corrected = 0.081). Taken together, dietary EP supplementation at 1000 mg/kg level promoted the relative weight of bursa of Fabricius may be involved in improving the immune function of broilers. These findings provided a reference for further exploring the specific molecular mechanism of EP that affecting the organ development in broilers.

Selenium Deficiency Causes Inflammatory Injury in the Bursa of Fabricius of Broiler Chickens by Activating the Toll-like Receptor Signaling Pathway.

The aim of our study was to observe the effect of selenium (Se) deficiency on inflammatory injury in the bursa of Fabricius of broiler chickens and to determine the role of the Toll-like receptor (TLR)/myeloid differential protein-88 (MyD88)/nuclear factor-κB (NF-κB) signaling pathway during this process. Here, we revealed that severe inflammatory injury occurred in the broiler bursa of Fabricius with Se deficiency via histopathology. Moreover, the ultrastructural pathological results showed that the nuclear, mitochondrial, endoplasmic reticulum and cytomembrane structures were damaged to varying degrees. Additionally, interleukin-2 (IL-2), interleukin-6 (IL-6), and interferon (IFN-γ) mRNA expression was markedly upregulated in the broiler bursa of Fabricius with Se deficiency. Furthermore, TLR, toll-interleukin-1 receptor domain-containing adapter-inducing interferon-β (TRIF), MyD88, and NF-κB mRNA expression was also markedly elevated in the broiler bursa of Fabricius with Se deficiency. The above results suggested that Se deficiency increases the expression of numerous proinflammatory cytokines and is probably due to the activation of the TLR/MyD88/NF-κB signaling pathway, which causes inflammatory injury in the bursa of Fabricius of broiler chickens. Our findings provide a theoretical reference for further studying the underlying mechanism of Se deficiency-induced inflammatory injury in the bursa of Fabricius of broiler chickens.

Regulation of H2S-induced necroptosis and inflammation in broiler bursa of Fabricius by the miR-15b-5p/TGFBR3 axis and the involvement of oxidative stress in this process

Hydrogen sulfide (H2S) is an air pollutant, having toxic effects on immune system. Necroptosis has been discussed as a new form of cell death and plays an important role in inflammation. To investigate the mechanism of H2S-induced immune injury, and the role of microRNAs (miRNAs) in this process, based on the results of high-throughput sequencing, we selected the most significantly changed miR-15b-5p for subsequent experiments. We further predicted and determined the targeting relationship between miR-15b-5p and TGFBR3 in HD11 through miRDB, Targetscan and dual-luciferase, and found that miR-15b-5p is highly expressed in H2S-induced necroptosis and inflammation. To understand whether miR-15b-5p/TGFBR3 axis could involve in the process of necroptosis and inflammation, we further revealed that the high expression of miR-15b-5p and the knockdown of TGFBR3 can induce necroptosis. Nec-1 treatment enhanced the survival rate of cells. Notably, H2S exposure induces oxidative stress and activates the TGF-β pathway, which are collectively regulated by the miR-15b-5p/TGFBR3 axis. Our present study provides a new perspective for necroptosis regulated by the miR-15b-5p/TGFBR3 axis and reveals a new form of inflammation regulation in immune diseases.

Marine algal polysaccharides alleviate aflatoxin B1-induced bursa of Fabricius injury by regulating redox and apoptotic signaling pathway in broilers

Aflatoxin B1 (AFB1) causes toxic effect and leads to organ damage in broilers. Marine algal polysaccharides (MAP) of Enteromorpha prolifera exert multiple biological activities, maybe have a potential detoxification effect on AFB1, but the related research in broilers is extremely rare. Therefore, the purpose of this study was to investigate whether MAPs can alleviate AFB1-induced oxidative damage and apoptosis of bursa of Fabricius in broilers. A total of 216 five-week-old male indigenous yellow-feathered broilers (with average initial body weight 397.35 ± 6.32 g) were randomly allocated to one of three treatments (6 replicates with 12 broilers per replicate), and the trial lasted 4 wk. Experimental groups were followed as basal diet (control group); basal diet mixed with 100 μg/kg AFB1 (AFB1 group, the AFB1 is purified form); basal diet with 100 μg/kg AFB1 + 2,500 mg/kg MAPs (AFB1 + MAPs group). The results showed that the diet with AFB1 significantly decreased the relative weight of bursa of Fabricius (P < 0.05), antioxidant enzymes activities of total superoxide dismutase (T-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST), and total antioxidation capacity (T-AOC), while increased malondialdehyde (MDA) content (P < 0.05). Besides, compared with AFB1 group, dietary MAPs improved the relative weight of bursa of Fabricius and activities of antioxidant enzymes (T-SOD, GSH-Px, CAT, GST) with decreased MDA contents (P < 0.05). Moreover, the consumption of AFB1 downregulated the mRNA expression of SOD1, SOD2, GSTA3, CAT1, GPX1, GPx3, GSTT1, Nrf2, HO-1, and p38MAPK (P < 0.05). Dietary MAPs upregulated the mRNA expression of SOD2, GSTA3, CAT1, GPX1, GSTT1, p38MAPK, Nrf2, and HO-1 in comparison with AFB1 group (P < 0.05). The histological analysis confirmed restoration of apoptotic cells of bursa of Fabricius (P < 0.01), which seen with MAPs supplemented broilers. Besides, dietary MAPs down-regulated the mRNA expression of caspase-3 and Bax (P < 0.05), while up-regulated the mRNA expression of Bcl-2 (P < 0.05) compared with AFB1 group. In addition, according to protein expression results, dietary MAPs up-regulated the protein expression level of antioxidant and apoptosis-associated proteins (Nrf2, HO-1, p38MAPK, Bcl-2) (P < 0.01), but down-regulated the protein expression level of caspase-3 and Bax (P < 0.01). In conclusion, dietary MAPs alleviated AFB1-induced bursa of Fabricius injury through regulating Nrf2-mediated redox and mitochondrial apoptotic signaling pathway in broilers.

Effect of Intermittent and Mild Cold Stimulation on the Immune Function of Bursa in Broilers.

Simple SummaryCold stress has an adverse effect on immune, antioxidant, and neuroendocrine systems as well as growth performance of broilers. Much attention was focused on how to improve the cold resistance of animals. However, it is not clear how intermittent and mild cold stimulation regulate the immune function. Therefore, the present study was designed to investigate the effect of intermittent and mild cold stimulation on the immune function of bursa in broilers. Our results indicated that the intermittent and mild cold stimulation (IMCS) could help broilers adapt to the low ambient temperature and maintain homeostasis by modulating the production of Toll-like receptors (TLRs), cytokines, and avian β-defensins (AvBDs) in the bursa of broilers. We expect to find a way to promote the establishment of cold adaptation through repeated intermittent cold trainings.Cold stress causes growth performance to decrease and increases production costs. Cold adaptation can enhance immune function and alleviate the negative impact caused by the stress condition. The study investigated the effect of intermittent and mild cold stimulation on the immune function of the bursa of Fabricius in broilers. A total of 400 healthy one-day-old broilers were divided into the control group (CC) and cold stimulation (CS) groups. The CC group was raised at a conventional raising temperature of broilers, while the CS groups were raised at 3°C below the temperature of the CC for three-, four-, five-, or six-hour periods at one-day intervals from 15 to 35 days of age (D35), denoted CS3, CS4, CS5, and CS6, respectively. Subsequently, they were raised at 20°C from 36 to 49 days of age (D49). The expression levels of TLRs, cytokines, and AvBDs were determined to access the immune function of bursa in broilers. After 21-day IMCS (at D36), the expression levels of TLR1, TLR15 and TLR21, interleukin (IL)-8, and interferon (IFN)-γ, as well as AvBD8 in CS groups, were lower than those in CC (p < 0.05). The expression levels of TLR3, TLR4 and TLR7, were decreased in the CS3, CS5, and CS6 groups (p < 0.05), but there were no significant differences in both the CC and CS4 groups (p > 0.05). When the IMCS ended for 14 days (at D49), the expression levels of TLR2, TLR3, TLR5, TLR7, TLR15, and TLR21, and IL-8, as well as AvBD2, AvBD4 and AvBD7 in CS groups, were lower than those in CC (p < 0.05). In addition to CS4, the expression levels of TLR1, IFN-γ, and AvBD8 in CS3, CS5, and CS6 were still lower than those in CC (p < 0.05). We concluded that the intermittent and mild cold stimulation could regulate immunoreaction by modulating the production of TLRs, cytokines, and AvBDs in the bursa, which could help broilers adapt to low ambient temperature and maintain homeostasis.

Hydrogen sulfide inhalation-induced immune damage is involved in oxidative stress, inflammation, apoptosis and the Th1/Th2 imbalance in broiler bursa of Fabricius

Hydrogen sulfide (H2S) is widely accepted to be a signaling molecule that exhibits some potentially beneficial therapeutic effects at physiological concentrations. At elevated levels, H2S is highly toxic and has a negative effect on human health and animal welfare. Studies have shown that H2S exposure induces an immune function in mice, but there are few studies of the effect of continuous H2S exposure on immune organs in poultry. In this study, one-day-old broilers were selected and exposed to 4 or 20 ppm of H2S gas for 14, 28 and 42 days of age. After exposure, the bursa of Fabricius (BF) was harvested. The results showed that continuous H2S exposure reduced the body weight, abdominal fat percentage, and antibody titer in broilers. H2S exposure also decreased mRNA expression of IgA, IgM and IgG in the broiler BF. A histological study revealed obvious nuclear debris, and a few vacuoles in the BF, and an ultrastructural study revealed mitochondrial and nuclear damage to BF cells after H2S exposure for 42 d. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay suggested H2S exposure remarkably increased the number of TUNEL positive nuclei and significantly increased apoptotic index. The expression of apoptotic genes also confirmed that H2S inhalation damaged the broiler BF. Increased cytokines and reduced antioxidant responses were detected in the BF after exposure to H2S. Cytokines promoted inflammation and caused a Th1/Th2 imbalance. We suggest that continuous H2S intoxication triggers oxidative stress, inflammation, apoptosis and a Th1/Th2 imbalance in the BF, leading to immune injury in broilers.

The molecular mechanism of cell cycle arrest in the Bursa of Fabricius in chick exposed to Aflatoxin B1

Aflatoxin B1 shows potent hepatotoxic, carcinogenic, genotoxic, immunotoxic potential in humans and many species of animals. The aim of this study was to clarify the underlying mechanism of G0G1 phase and G2M phase arrest of cell cycle in the bursa of Fabricius in broilers exposed to dietary AFB1. 144 one-day-old healthy Cobb broilers were randomly divided into two groups and fed on control diet and 0.6 mg·Kg−1 AFB1 diet for 3 weeks. Histological observation showed that AFB1 induced the increase of nuclear debris and vacuoles in lymphoid follicle of BF. Results of flow cytometry studies showed that bursal cells arrested in G2M phase at 7 days of age and blocked in G0G1 phase at 14 and 21 days of age following exposure to AFB1. The qRT-PCR analysis indicated that cell cycle arrested in G2M phase via ATM-Chk2-cdc25-cyclin B/cdc2 pathway, and blocked in G0G1 phase through ATM-Chk2-cdc25-cyclin D/CDK6 pathway and ATM-Chk2-p21-cyclin D/CDK6 route. In a word, our results provided new insights that AFB1 diet induced G2M and G0G1 phase blockage of BF cells in different periods, and different pathways were activated in different arrested cell cycle phase.

Evaluation of the Growth of the Bursa of Fabricius in Broilers Reared under Different Light Photoperiods

Evaluation of the Growth of the Bursa of Fabricius in Broilers Reared under Different Light Photoperiods

Toxic effect of NiCl2 on development of the bursa of Fabricius in broiler chickens

This study was conducted with objective of evaluating the toxic effects of nickel chloride (NiCl2) on development of bursa of Fabricius in broilers fed on diets supplemented with 0, 300, 600 and 900 mg/kg of NiCl2 for 42 days by using the methods of experimental pathology, flow cytometry (FCM), and quantitative real-time polymerase chain reaction (qRT-PCR). The results showed that dietary NiCl2 in 300 mg/kg and over induced toxic suppression in the bursal development, which was characterized by decreasing lymphocytes histopathologically and relative weight, increasing G0/G1 phase (a prolonged nondividing state), reducing S phase (DNA replication) and proliferating index, and increasing percentages of apoptotic cells. Concurrently, the mRNA expression levels of bax, cytochrome c (cyt c), apoptotic peptidase activating factor 1 (Apaf-1), caspase-3, caspase-6, caspase-7 and caspase-9 were increased and the bcl-2 mRNA expression levels were decreased. The toxic suppression of bursal development finally impaired humoral immunity duo to the reduction of B lymphocyte population and B lymphocyte activity in the broiler chicken. This study provides new evidences for further studying the effect mechanism of Ni and Ni compoundson B-cell or bursa of Fabricius.

Aflatoxin B1 affects apoptosis and expression of Bax, Bcl-2, and Caspase-3 in thymus and bursa of fabricius in broiler chickens.

Aflatoxin B1 is known as a mycotoxin that develops various health problems of animals, the effects of AFB1 on thymus and bursa of Fabricius in chickens are not clear. The objective of this study was to investigate the apoptosis of thymus and bursa of Fabricius in broilers fed with AFB1 . Two hundred Avian broilers were randomly divided into four groups of 50 each, namely control group and three AFB1 groups fed with 0.15 mg, 0.3 mg, and 0.6 mg AFB1 /kg diet, respectively. In this study, flow cytometer and immunohistochemical approaches were used to determine the percentage of apoptotic cells and the expression of Bax, Bcl-2, and Caspase-3. The results showed that consumption of AFB1 diets results in increased percentage of apoptotic cells and increased expression of Caspase-3 in both thymus and bursa of Fabricius. The expression of Bax was increased and the expression of Bcl-2 was decreased in the thymus, but no significant changes in Bax and Bcl-2 expression were observed in the bursa of Fabricius when broilers fed with AFB1 . These findings suggest that adverse effects of AFB1 on thymus and bursa of Fabricius in broilers were confirmed by increased apoptotic cells and abnormal expression of Caspase-3. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1113-1120, 2016.

Melatonin plays a critical role in inducing B lymphocyte proliferation of the bursa of Fabricius in broilers via monochromatic lights

To study the role of melatonin in the monochromatic light-induced B lymphocyte proliferation of bursa, a total of 360 newly hatched broilers, including intact, sham-operated, and pinealectomized groups, were exposed to blue light (BL), green light (GL), red light (RL) and white light (WL) from a light-emitting diode system for 14d. Both in vivo and in vitro studies showed that the percentage of proliferating cell nuclear antigen (PCNA)-immunoreactive lymphocytes and the lymphocyte proliferation in response to lipopolysaccharide in the bursa of broilers in the GL intact group was the highest values among the different intact groups with altered plasma melatonin levels. Additionally, the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and total antioxidant capability (T-AOC) were the highest, whereas malondialdehyde (MDA) content and inducible nitric oxide synthase (iNOS) expression were significantly decreased in the GL intact group. After pinealectomy, the levels of SOD, GSH-Px and T-AOC decreased remarkably in the various light-treatment groups, whereas the MDA content and iNOS expression significantly increased. The administration of exogenous melatonin (250pg/mL) in vitro also significantly enhanced the bursal B lymphocyte proliferation. These findings suggest that GL illumination effectively elevates the antioxidative capacity to promote B lymphocyte proliferation of bursa in young broilers, which might depend on enhanced melatonin secretion.

Effect of selenium supplementation on aflatoxin B1-induced histopathological lesions and apoptosis in bursa of Fabricius in broilers

To investigate the effects of sodium selenite against aflatoxin B1 (AFB 1), 200 male Avian broilers, divided into five groups, were fed with basal diet (control group), 0.3 mg/kg AFB1 (AFB1 group), 0.3 mg/kg AFB1 + 0.2 mg/kg Se (+Se group I), 0.3 mg/kg AFB1 + 0.4 mg/kg Se (+Se group II) and 0.3 mg/kg AFB1 + 0.6 mg/kg Se (+Se group III), respectively. Compared with the control group, decreased relative weight of bursa of Fabricius and contents of serum immunoglobulin, more vacuoles and debris in the bursal lymphoid follicle, and increased percentage of apoptotic bursal cells were observed in the AFB1 group. Sodium selenite, however, could increase the relative weight of bursa of Fabricius and contents of serum immunoglobulin, and ameliorate histopathological lesions. The percentages of apoptotic bursal cells, through flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method, in the three +Se groups were lower than those in the AFB 1 group. Compared with the AFB 1 group, moreover, the mRNA expressions of Bax and Caspase-3 by qRT-PCR in the three +Se groups were decreased, while the expression of Bcl-2 was increased. The results indicate that sodium selenite in diet can protect chicken from AFB 1-induced impairment of humoral immune function by reducing bursal histopathological lesions and percentages of apoptotic bursal cells.

Pathological Changes and the Effects of Ascorbic Acid on Lesion Scores of Bursa of Fabricius in Broilers Under Chronic Heat Stress

Pathological Changes and the Effects of Ascorbic Acid on Lesion Scores of Bursa of Fabricius in Broilers Under Chronic Heat Stress

Histomorphology of bursa of Fabricius: effects of stock densities on commercial broilers

During the past few years, there has been considerable interest on the effects of stocking density on broiler behavior and immunity. Stress may cause immunodeficiency by affecting cell and humoral responses, as well as body weight decrease, and foot-pad dermatitis. The aim of this study was to study histomorphological changes of the bursa of Fabricius in broilers submitted to three different stocking densities (10, 15, and 20 birds/m 2 ) from one to 42 days of age. Three birds from each group were sacrifieced on days 7 and 42. The bursa was collected, fixed, and processed for histomorphometric assessment using a Kontrom KS 400 image analyzer. Data were analyzed by Biostat 3.0 (Tukey Test). The results of average cortical area percentage in bursal follicles of 6week-old birds were 45.12a (10 birds/m 2 ), 30.43b (15 birds/m 2 ), and 23.77b (20 birds/m 2 ). Average body weight was 2.58a kg (10 birds/m 2 ), 2.56a Kg (15 birds/m 2 ), and 2.47b Kg (20 birds/m 2 ), respectively. The percentage of foot-pad dermatitis in 6-week-old birds was 3.33a (10 birds/m 2 ), 17.76b (15 birds/m 2 ), and 49.17c (20 birds/m 2 ). These differences were statistically significant at a P<0.05 level. Under these experimental conditions,, it was concluded that the best stocking density to produce broilers is between 10-15 birds per square meter.