Changes of IgA+ cells and cytokines in the cecal tonsil of broilers fed on diets supplemented with vanadium

Expression levels of key immune indicators and immune checkpoints in manganese-exposed rats

Manganese is essential trace elements, to participate in the body a variety of biochemical reactions, has important physiological functions, such as stimulate the immune cell proliferation, strengthen the cellular immunity, etc. However, excessive manganese exposure can cause damage to multiple systems of the body.The immune system is extremely vulnerable to external toxicants, however manganese research on the immune system are inadequate and biomarkers are lacking. Therefore, here we applied a manganese-exposed rat model to make preliminary observations on the immunotoxic effects of manganese. We found that manganese exposure inhibited humoral immune function in rats by decreasing peripheral blood IgG (ImmunoglobulinG, IgG), IgM (ImmunoglobulinM, IgM) and complement C3 levels; It also regulates rat cellular immune activity by influencing peripheral blood, spleen, and thymus T cell numbers and immune organ ICs (Immune Checkpoints, ICs) and cytokine expression. Furthermore, it was revealed that the impact of manganese exposure on the immune function of rats exhibited a correlation with both the dosage and duration of exposure. Notably, prolonged exposure to high doses of manganese had the most pronounced influence on rat immune function, primarily manifesting as immunosuppression.The above findings suggest that manganese exposure leads to impaired immune function and related changes in immune indicators, or may provide clues for the discovery of its biomarkers.

Evaluation of immunotoxicity of sodium metavanadate following drinking water exposure in female B6C3F1/N mice in a 28-day study

Sodium metavanadate (NaVO3 ) is a pentavalent vanadium compound used in the metal industry and dietary supplements; human exposure occurs through inhalation of fumes and dust and ingestion of NaVO3 -containing products. The objective of this study was to assess the potential immunotoxicity of NaVO3 . Female B6C3F1/N mice were exposed to 0-500 ppm NaVO3 in drinking water for 28 days and evaluated for effects on immune cell populations and innate, cellular-mediated, and humoral-mediated immunity. There was a decreasing trend in body weight (BW) and BW gain in NaVO3 exposed mice, with a decrease (p ≤ 0.05) in BW gain at ≥250 ppm, relative to control. Conversely, increasing trends in spleen weights and an increase (p ≤ 0.05) in the spleen:BW ratio at ≥250 ppm NaVO3 were observed. NaVO3 exposure altered antibody production against sheep red blood cells (SRBC). Antibody forming cells (AFC)/106 spleen cells exhibited a decreasing trend, with a decrease (p ≤ 0.05) at 500 ppm NaVO3 , concurrent with an increase in percent B cells. NaVO3 had no effect on the serum anti-SRBC IgM antibody titers or anti-keyhole limpet hemocyanin antibody production. Exposure to NaVO3 decreased the percentage of natural killer cells at all dose levels (p ≤ 0.05), with no effect on the lytic activity. NaVO3 altered T-cell populations at 500 ppm but had no effect on T-cell proliferative responses or the lytic activity of cytotoxic T cells. Collectively, these data indicate that NaVO3 exposure can adversely affect the immune system by inducing alterations in humoral-mediated immunity, specifically the AFC response, with no effect on cell-mediated or innate immunity.

Prenatal and postnatal exposure to vanadium and the immune function of children

BACKGROUND

The immunotoxicity induced by vanadium exposure have been reported in some toxicology researches. However, evidence from population-based epidemiological studies was lacking.

METHODS

This study was conducted to assess the associations between prenatal and postnatal exposure to vanadium and immune function of children. A total of 407 pre-school aged children were followed, whose peripheral blood was collected for T lymphocyte subsets and inflammatory cytokines analysis, as well as vanadium concentration measurement. Maternal urine samples were also collected to measure vanadium concentration. We used generalized linear models to evaluate the associations of maternal and children vanadium concentration with children's immune function. Stratification analysis was further conducted to explore the potential gender-specific effects.

RESULTS

The geometric means of vanadium concentration in maternal urine and children plasma were 0.85 and 1.12 μg/L, respectively. Maternal urinary vanadium was inversely associated with the percentage of CD3⁺CD4⁺ cells [-5.53 % (-10.38 %, -0.41 %)] and absolute counts of CD3⁺ cells [-2.43 % (-5.05 %, 0.25 %)], and we only observed significant negative associations in males when stratifying by fetal gender. Children plasma vanadium was also associated with reduced absolute counts of CD3⁺ cells [-5.25 % (-9.57 %, -0.73 %)], but gender-specific effects were not observed. No significant associations of vanadium exposure with cytokines were found.

CONCLUSIONS

Prenatal and postnatal exposure to vanadium had suppressive impacts on childhood cellular immune. Further studies are needed to confirm our findings.

Effect of feed supplementation with zinc glycine chelate and zinc sulfate on cytokine and immunoglobulin gene expression profiles in chicken intestinal tissue

The aim of the study was to evaluate the effect of inorganic and organic forms of Zn on the expression of cytokines (IL-2, TNF-α, IFN-γ, IL-12, IL-17, IL-4, IL-10, and TGF-β) and immunoglobulins (IgA and IgG) in the tissues of the small intestine (jejunum and ileum) of broiler chickens. In the experiment, 90 broiler chickens were divided into 4 experimental groups and a control group, with 18 birds each. The birds received Zn supplements in inorganic form with and without phytase (ZnSO4 and ZnSO4 + F), and in organic form with glycine, with and without phytase (Zn-Gly and Zn-Gly + F). The total rearing period was 42 days. Quantitative real-time (RT)-PCR was used to measure the expression of the cytokines and immunoglobulins. The differences between the results obtained for the control and experimental groups, between the groups receiving ZnSO4 and Zn-Gly, and between groups ZnSO4-F and Zn-Gly-F were analyzed statistically. High relative expression of IL-2 was observed for the chickens in the groups receiving ZnSO4-F, Zn-Gly, and Zn-Gly-F on d 42 in comparison to the control group. High relative expression of TNF-α, IL-12, and IL-17 was noted in the group that received ZnSO4 + F. High expression of IgG, IgA, IL-4, TGF-β, and IL-10 was noted in the groups of chickens that received feed supplemented with Zn-Gly and Zn-Gly + F chelates on d 42 of the study in comparison to the control group. In conclusion, supplementation with Zn-Gly chelates can ensure Th1 and Th2 balance during the immune response in the gut-associated lymphoid tissue (GALT), and, by increasing IgA and IgG expression, also can stimulate potentiation of the immune response involved in passive protection of the body from infection. In contrast, the use of inorganic forms of Zn, in the form of sulfates, can induce local inflammatory processes in the intestines, which, in the case of long-term supplementation, lead to the development of infections.

Sodium selenite prevents suppression of mucosal humoral response by AFB1 in broiler's cecal tonsil

Aflatoxin B₁ (AFB₁), the most common mycotoxin in human food and animal feed, produces hepatotoxic, genotoxic and immunosuppressive effects in multiple species. Selenium (Se) has emerged as an important element in the dietary prevention of various toxic agents. The present study was designed to scrutinize the protective effects of sodium selenite on the histological lesions and suppression of mucosal humoral response in the cecal tonsil generated by AFB₁. A total of 156 one-day-old broilers were divided into four groups and fed on basal diet (control group), 0.6 mg/kg AFB₁ (AFB₁ group), 0.4 mg/kg Se supplement (+Se group), and 0.6 mg/kg AFB₁ + 0.4 mg/kg Se supplement (AFB₁+Se group) respectively for 21 days. Our results showed that 0.4 mg/kg Se supplement in broiler's diets could improve the AFB₁-induced histological lesions in the cecal tonsils including the depletion of lymphocytes in the lymphatic nodules as well as the shedding of microvilli in the absorptive cells. Moreover, Se could restore the decreased number of IgA+ cells and expression levels of pIgR, IgA, IgG, and IgM mRNA induced by AFB₁ to be close to those in the control group. These results demonstrated that 0.4 mg/kg supplemented dietary Se in the form of sodium selenite could protect the cecal tonsils from the histological lesions and suppression of the mucosal humoral response provoked by 0.6 mg/kg AFB₁. Our study may provide new experimental evidences for better understanding of AFB₁-induced damage of mucosal immunity and protective effect of Se against this toxin.

Effect of Vanadium and Tea Polyphenols on Intestinal Morphology, Microflora and Short-Chain Fatty Acid Profile of Laying Hens

Vanadium (V) is a trace element which can induce dysfunction of gastro-intestine and egg quality deterioration of laying hens. This study was conducted to determine the effect of tea polyphenols (TP) on intestinal morphology, microflora, and short-chain fatty acid (SCFA) profile of laying hens fed vanadium containing diets. A total of 120 Lohman laying hens (67-week-old) were randomly divided into 4 groups with 6 replicates and 5 birds each for a 35-day feeding trial. The dietary treatments were as follows: (1) control (CON), fed a basal diet; (2) vanadium treatment (V10), CON +10 mg V/kg; (3) TP treatment 1 (TP1): V10 + 600 mg TP/kg; (4) TP treatment 2 (TP2): V10 + 1000 mg TP/kg. Fed 10 mg V/kg diets to laying hens did not affect the cecum flora diversity index (H), degree of homogeneity (EH), and richness (S), but hens fed TP2 diet decreased the H, EH, and S (P < 0.05). The cecum butyrate acid concentration was lower in V10 treatment and higher in TP2 treatment (P < 0.05). Addition of 10 mg/kg V resulted in an increased (P < 0.01) duodenal cell apoptosis rate, and 1000 mg/kg TP supplementation overcame (P < 0.01) this reduction effect induced by vanadium. The results indicated that supplementation of 10 mg/kg vanadium increased duodenal cell apoptosis and reduced cecum butyrate acid content. Addition of 1000 mg/kg TP increased the SCFA production to affect cecum flora ecology and protected the duodenal cell from excess apoptosis caused by vanadium.

Vanadium toxicity in the thymic development

The purpose of this study was to define the toxic effects of vanadium on thymic development in broilers fed on diets supplemented with 0, 5, 15, 30, 45 and 60 mg/kg of vanadium for 42 days. We examined the changes of relative weigh, cell cycle phase, apoptotic cells, and protein expression of Bcl-2, Bax, and caspase-3 in the thymus by the methods of flow cytometry, TUNEL (terminal-deoxynucleotidyl transferase mediated nick end labeling) and immunohistochemistry. The results showed that dietary high vanadium (30 mg/kg, 45 mg/kg and 60 mg/kg) caused the toxic effects on thymic development, which was characterized by decreasing relative weigh, increasing G0/G1 phase (a prolonged nondividing state), reducing S phase (DNA replication) and proliferating index (PI), and increasing percentages of apoptotic thymocytes. Concurrently, the protein expression levels of Bax and caspase-3 were increased, and protein expression levels of Bcl-2 were decreased. The thymic development suppression caused by dietary high vanadium further leads to inhibitive effects on T lymphocyte maturity and activity, and cellular immune function. The above-mentioned results provide new evidences for further understanding the vanadium immunotoxicity. In contrast, dietary 5 mg/kg vanadium promoted the thymic development by increasing relative weigh, decreasing G0/G1 phase, increasing S phase and PI, and reducing percentages of apoptotic thymocytes when compared to the control group and high vanadium groups.

Role of monochromatic light on development of cecal tonsil in young broilers

Previously, the different monochromatic lights have been demonstrated to affect splenocyte proliferation and melatonin (MEL) secretion in broilers. The present study was designed to evaluate the effects of different monochromatic lights on the development and immune function of broiler cecal tonsils, and to disclose the mechanisms underlying these phenomena. A total of 185 broilers (P0) including intact, sham-operated, and pinealectomized groups were exposed to blue light (BL), green light (GL), red light (RL), and white light (WL) by a light-emitting diode system for 14 days. Compared with RL groups, the GL in the intact and sham-operated groups showed larger follicle areas (66.70%), higher percentages of proliferating cell nuclear antigen (PCNA)-positive cells (33.33%), increased numbers of IgA(+) cells (48.60%), and increased antioxidase activity (33.33%-61.37%), whereas, the density of iNOS and MDA content in GL were lower (43.63%-54.43%) than that of RL. In contrast, after pinealectomy, the area of follicles, the percentage of PCNA-positive cells, the number of IgA(+) cells, and the antioxidase activity decreased in the different light treatments, but the density of iNOS and MDA content increased substantially. There was no significant difference in these parameters between broilers exposed to GL and other lights (P = 0.085-1.000). The results suggested that the enhanced effects of GL on the development and immune function of cecal tonsils in young broilers were mediated by elevated antioxidative status via up-regulation of MEL.

Potential directions for chicken immunology research

The importance of poultry, particularly chicken, as a food source continues to increase globally. Moreover, zoonotic infectious diseases such as avian influenza virus not only continue to impact poultry production, but also pose an increasing threat to public health. This review discusses the importance of poultry in both agricultural and public health arenas. Recent developments in avian immunology are described, with an emphasis on host-pathogen interactions and noting differences from mammalian systems. Next generation technologies including functional genomics and targeted gene disruption (e.g. zinc finger nucleases and meganucleases) are discussed as new approaches for not only understanding immune responses in poultry, but also as novel disease intervention strategies.