Effects of aflatoxin B1 on the cell cycle distribution of splenocytes in chickens

Insights into microstructure and expression of markers of proliferation, apoptosis and T cells in the spleen of cattle egret (Bubulcus ibis)

The spleen is the largest secondary lymphoid organ with significant roles in pathogen clearance. It is involved in several avian diseases. The cattle egret is a wild insectivorous bird of agricultural and socioeconomic importance. Data related to microstructural features of cattle egret spleen are lacking. The present study investigated the gross anatomical, histological and immunohistochemical characteristics of the cattle egret spleen. Proliferation (PCNA and PHH3), apoptosis (cleaved caspase 3, C.CASP3) and T-cell (CD3 and CD8) markers were assessed. Grossly, the spleen appeared brownish red, oval-shaped and located at the oesophago-proventricular junction. Histologically, the spleen was surrounded by a thin capsule sending a number of trabeculae which contained branches of the splenic vessels. The white pulp consisted of the periarteriolar lymphoid sheath and periellipsoidal lymphatic sheath (PELS). The red pulp was formed of sinusoids and cords. The penicillar capillaries, which represent the terminal segments of the splenic arterial tree were highly branched, wrapped by prominent ellipsoids and directly connected to the splenic sinusoids, suggesting a closed type of circulation. Immunohistochemically, proliferating cell nuclear antigen (PCNA)-expressing cells were distributed with high counts throughout the splenic parenchyma, being highest within the splenic cords and PELS. Both PHH3- and C.CASP3-expressing cells revealed a similar pattern to that of PCNA, although with fewer counts. Large numbers of T cells were observed throughout the splenic parenchyma, mainly within the cords, as revealed by CD3 and CD8 immunoreaction. The present study provides a clear insight into the precise structure of the spleen in cattle egrets and thus improves our understanding about birds' immunity.

Hidden Hazards Revealed: Mycotoxins and Their Masked Forms in Poultry

The presence of mycotoxins and their masked forms in chicken feed poses a significant threat to both productivity and health. This review examines the multifaceted impacts of mycotoxins on various aspects of chicken well-being, encompassing feed efficiency, growth, immunity, antioxidants, blood biochemistry, and internal organs. Mycotoxins, toxic substances produced by fungi, can exert detrimental effects even at low levels of contamination. The hidden or masked forms of mycotoxins further complicate the situation, as they are not easily detected by conventional methods but can be converted into their toxic forms during digestion. Consequently, chickens are exposed to mycotoxin-related risks despite apparently low mycotoxin levels. The consequences of mycotoxin exposure in chickens include reduced feed efficiency, compromised growth rates, impaired immune function, altered antioxidant levels, disturbances in blood biochemical parameters, and adverse effects on internal organs. To mitigate these impacts, effective management strategies are essential, such as routine monitoring of feed ingredients and finished feeds, adherence to proper storage practices, and the implementation of feed detoxification methods and mycotoxin binders. Raising awareness of these hidden hazards is crucial for safeguarding chicken productivity and health.

Spirulina platensis ameliorates hepatic oxidative stress and DNA damage induced by aflatoxin B1 in rats

Aflatoxin B1 (AFB1) is a widely distributed mycotoxin, causing hepatotoxicity and oxidative stress. One of the most famous unicellular cyanobacteria is Spirulina platensis (SP) which is well known for its antioxidant characteristics against many toxicants. Therefore, this study aimed to investigate the antioxidant potential and hepatoprotective ability of SP against oxidative stress and cytotoxicity in male Wistar albino rats intraperitoneally injected with AFB1. Rats were separated into five groups as follows: negative control administered with saline; SP (1000 mg/kg BW) for two weeks; AFB1 (2.5 mg/kg BW) twice on days 12 and 14; AFB1 (twice) + 500 mg SP/kg BW (for two weeks) and AFB1 (twice) + 1000 mg SP/kg BW (for two weeks). Liver and blood samples were assembled for histological and biochemical analyses. AFB1 intoxicated rats showed a marked elevation in serum biochemical parameters (ALP, ALT, and AST), hepatic lipid peroxidation (MDA and NO), and proliferating cell nuclear antigen (PCNA) indicating DNA damage. Moreover, AFB1 caused suppression of antioxidant biomarkers (SOD, GHS, GSH-Px, and CAT). However, the elevated serum levels of biochemical parameters and PCNA expression were reduced by SP. Moreover, SP lowered oxidative stress and lipid peroxidation markers in a dose-dependent manner. To sum up, SP supplementation is capable of decreasing AFB1 toxicity through its powerful antioxidant activity.

Mycotoxins and cellular senescence: the impact of oxidative stress, hypoxia, and immunosuppression

Mycotoxins induce oxidative stress, hypoxia, and cause immunosuppressive effects. Moreover, emerging evidence show that mycotoxins have a potential of inducing cellular senescence, which are involved in their immunomodulatory effects. Mycotoxins upregulate the expression of senescence markers γ-H2AX, senescence-associated β-galactosidase, p53, p16, and senescence-associated secretory phenotype (SASP) inflammatory factors. Moreover, mycotoxins cause senescence-associated cell cycle arrest by diminishing cyclin D₁ and Cdk4 pathways, as well as increasing the expression of p53, p21, and CDK6. Mycotoxins may induce cellular senescence by activating reactive oxygen species (ROS)-induced oxidative stress. In addition, hypoxia acts as a double-edged sword on cell senescence; it could both act as the stress-induced senescence and also hinder the onset of cellular senescence. The SASP inflammatory factors have the ability to induce an immunosuppressive environment, while mycotoxins directly cause immunosuppression. Therefore, there is a potential relationship between mycotoxins and cellular senescence that synergistically cause immunosuppression. However, most of the current studies have involved the effect of mycotoxins on cell cycle arrest, but only limited in-depth research has been carried out to link the occurrence of this condition (cell cycle arrest) with cellular senescence.

AFB1 and OTA Promote Immune Toxicity in Human LymphoBlastic T Cells at Transcriptomic Level

Aflatoxin B1 (AFB1) and ochratoxin A (OTA) are typical contaminants of food and feed, which have serious implications for human and animal health, even at low concentrations. Therefore, a transcriptomic study was carried out to analyze gene expression changes triggered by low doses of AFB1 and OTA (100 nM; 7 days), individually and combined, in human lymphoblastic T cells. RNA-sequencing analysis showed that AFB1-exposure resulted in 99 differential gene expressions (DEGs), while 77 DEGs were obtained in OTA-exposure and 3236 DEGs in the combined one. Overall, 16% of human genome expression was altered. Gene ontology analysis revealed, for all studied conditions, biological processes and molecular functions typically associated with the immune system. PathVisio analysis pointed to ataxia telangiectasia mutated signaling as the most significantly altered pathway in AFB1-exposure, glycolysis in OTA-exposure, and ferroptosis in the mixed condition (Z-score > 1.96; adjusted p-value ≤ 0.05). Thus, the results demonstrated the potential DNA damage caused by AFB1, the possible metabolic reprogramming promoted by OTA, and the plausible cell death with oxidative stress prompted by the mixed exposure. They may be considered viable mechanisms of action to promote immune toxicity in vitro.

Integrated Profiles of Transcriptome and mRNA m6A Modification Reveal the Intestinal Cytotoxicity of Aflatoxin B1 on HCT116 Cells

Aflatoxin B1 (AFB1) is widely prevalent in foods and animal feeds and is one of the most toxic and carcinogenic aflatoxin subtypes. Existing studies have proved that the intestine is targeted by AFB1, and adverse organic effects have been observed. This study aimed to investigate the relationship between AFB1-induced intestinal toxicity and N6-methyladenosine (m6A) RNA methylation, which involves the post-transcriptional regulation of mRNA expression. The transcriptome-wide m6A methylome and transcriptome profiles in human intestinal cells treated with AFB1 are presented. Methylated RNA immunoprecipitation sequencing and mRNA sequencing were carried out to determine the distinctions in m6A methylation and different genes expressed in AFB1-induced intestinal toxicity. The results showed that there were 2289 overlapping genes of the differentially expressed mRNAs and differentially m6A-methylation-modified mRNAs. After enrichment of the signaling pathways and biological processes, these genes participated in the terms of the cell cycle, endoplasmic reticulum, tight junction, and mitophagy. In conclusion, the study demonstrated that AFB1-induced HCT116 injury was related to the disruptions to the levels of m6A methylation modifications of target genes and the abnormal expression of m6A regulators.

Compound mycotoxin detoxifier alleviating aflatoxin B1 toxic effects on broiler growth performance, organ damage and gut microbiota

The aim of this study was to evaluate the effects of compound mycotoxin detoxifier (CMD) on alleviating the toxic effect of aflatoxin B₁ (AFB₁) for broiler growth performance. One-kilogram CMD consists of 667 g aflatoxin B₁-degrading enzyme (ADE, 1,467 U/g), 200 g montmorillonite and 133 g compound probiotics (CP). The feeding experiment was divided into 2 stages (1-21 d and 22-42 d). In the early stage, a total of 300 one-day-old Ross broilers were randomly divided into 6 groups, 5 replications for each group, 10 broilers (half male and half female) in each replication. In the later feeding stage, about 240 twenty-two-day-old Ross broilers were randomly divided into 6 groups, 8 replications for each group, 5 broilers in each replication. Group A: basal diet; group B: basal diet with 40 μg/kg AFB₁; group C: basal diet with 1 g/kg CMD; groups D, E, and F: basal diet with 40 μg/kg AFB₁ plus 0.5, 1.0 and 1.5 g/kg CMD, respectively. The results indicated that AFB₁ significantly decreased average daily gain (ADG), protein metabolic rate, organ index of thymus, bursa of Fabricius (BF), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and catalase activities in serum, and increased AFB₁ residues in serum and liver (P < 0.05). Hematoxylin-Eosin (HE) staining analysis of jejunum, liver and kidney showed that AFB₁ caused the main pathological changes with different degrees of inflammatory cell infiltration. However, CMD additions could alleviate the negative effects of AFB₁ on the above parameters. The gut microbiota analysis indicated that AFB₁ could significantly increase the abundances of Staphylococcus-xylosu, Esherichia-coli-g-Escherichia-Shigella, and decrease Lactobacillus-aviarius abundance (P < 0.05), but which were adjusted to almost the same levels as the control group by CMD addition. The correlative analysis showed that Lactobacillus-aviarius abundance was positively correlated with ADG, SOD and BF (P < 0.05), whereas Staphylococcus-xylosus abundance was positively correlated with AFB₁ residues in serum and liver (P < 0.05). In conclusion, CMD could keep gut microbiota stable, alleviate histological lesions, increase growth performance, and reduce mycotoxin toxicity. The optimal CMD addition should be 1 g/kg in AFB₁-contaminated broilers diet.

Hypoxia and Cellular Senescence, Emerging Toxic Mechanisms of Mycotoxins and Toxins: A New Understanding of the Negative Immune Regulations

Mycotoxin contamination is an important issue that has plagued the world [...]

Integrated Transcriptome Analysis Reveals mRNA-miRNA Pathway Crosstalk in Roman Laying Hens' Immune Organs Induced by AFB1

Aflatoxin B1 (AFB1) is a widely distributed contaminant in moldy corn, rice, soybean, and oil crops. Many studies have revealed its adverse effects, such as carcinogenicity, immunotoxicity, and hepatotoxicity, on the health of humans and animals. To investigate the immunotoxic effects on chicken immune organs induced by AFB1, we integrated RNA and small-RNA sequencing data of the spleen and the bursa of Fabricius to elucidate the response of the differentially expressed transcriptional profiles and related pathways. AFB1 consumption negatively influenced egg quality, but no obvious organ damage was observed compared to that of the control group. We identified 3918 upregulated and 2415 downregulated genes in the spleen and 231 upregulated and 65 downregulated genes in the bursa of Fabricius. We confirmed that several core genes related to immune and metabolic pathways were activated by AFB1. Furthermore, 42 and 19 differentially expressed miRNAs were found in the spleen and the bursa of Fabricius, respectively. Differentially expressed genes and target genes of differentially expressed miRNAs were mainly associated with cancer progression and immune response. The predicted mRNA-miRNA pathway network illustrated the potential regulatory mechanisms. The present study identified the transcriptional profiles and revealed potential mRNA-miRNA pathway crosstalk. This genetic regulatory network will facilitate the understanding of the immunotoxicity mechanisms of chicken immune organs induced by high concentrations of AFB1.

Pumpkin extract and fermented whey individually and in combination alleviated AFB1- and OTA-induced alterations on neuronal differentiation invitro

Food and feed are daily exposed to mycotoxin contamination which effects may be counteracted by functional compounds like carotenoids and fermented whey. Among mycotoxins, the most toxic and studied are aflatoxin B1 (AFB1) and ochratoxin A (OTA), which neurotoxicity is not well reported. Therefore, SH-SY5Y human neuroblastoma cells ongoing differentiation were exposed during 7 days to digested bread extracts contained pumpkin and fermented whey, individually and in combination, along with AFB1 and OTA and their combination, in order to evaluate their presumed effects on neuronal differentiation. The immunofluorescence analysis of βIII-tubulin and dopamine markers pointed to OTA as the most damaging treatment for cell differentiation. Cell cycle analysis reported the highest significant differences for OTA-contained bread compared to the control in phase G₀/G₁. Lastly, RNA extraction was performed and gene expression was analyzed by qPCR. The selected genes were related to neuronal differentiation and cell cycle. The addition of functional ingredients in breads not only enhancing the expression of neuronal markers, but also induced an overall improvement of gene expression compromised by mycotoxins activity. These data confirm that in vitro neuronal differentiation may be impaired by AFB1 and OTA-exposure, which could be modulated by bioactive compounds naturally found in diet.

Fucoidan supplementation modulates hepato-renal oxidative stress and DNA damage induced by aflatoxin B1 intoxication in rats

Aflatoxins are a common food contaminant of global concern. Aflatoxin B₁ (AFB₁) intoxication is associated with serious health hazards. Recently, fucoidan (FUC) has gained much attention from pharmaceutical industry due to its promising therapeutic effects. The impacts of FUC on AFB₁-induced liver and kidney injures have not been sufficiently addressed. This research was conducted to evaluate the ameliorative effect of FUC in AFB1-induced hepatorenal toxicity model in rats over 14 days. Five groups were assigned; control, FUC (200 mg/kg/day, orally), AFB₁ (50 μg/kg, i.p.), and AFB₁ plus a low or high dose of FUC. AFB₁ induced marked hepatorenal injury elucidated by substantial alterations in biochemical tests and histological pictures. The oxidative distress instigated by AFB₁ enhanced production of malondialdehyde (MDA) and nitric oxide (NO) along with reduction in the reduced-glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) activities. DNA damage in the liver and kidney tissues has been demonstrated by overexpression of proliferating cell nuclear antigen (PCNA). Unambiguously, FUC consumption alleviates the AFB₁-induced mitochondrial dysfunction, oxidative harm, and apoptosis. These ameliorated effects are proposed to be attributed to fucoidan's antioxidant and anti-apoptotic activities. Our results recommend FUC supplementation to food because it exerts both preventive and therapeutic effects against AFB₁-induced toxicity.

Characteristics, Occurrence, Detection and Detoxification of Aflatoxins in Foods and Feeds

Mycotoxin contamination continues to be a food safety concern globally, with the most toxic being aflatoxins. On-farm aflatoxins, during food transit or storage, directly or indirectly result in the contamination of foods, which affects the liver, immune system and reproduction after infiltration into human beings and animals. There are numerous reports on aflatoxins focusing on achieving appropriate methods for quantification, precise detection and control in order to ensure consumer safety. In 2012, the International Agency for Research on Cancer (IARC) classified aflatoxins B1, B2, G1, G2, M1 and M2 as group 1 carcinogenic substances, which are a global human health concern. Consequently, this review article addresses aflatoxin chemical properties and biosynthetic processes; aflatoxin contamination in foods and feeds; health effects in human beings and animals due to aflatoxin exposure, as well as aflatoxin detection and detoxification methods.