A one-generation reproductive toxicity study of the mycotoxin ochratoxin A in Fischer rats.

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium molds. Grain-based foods account for most human dietary exposures to OTA. OTA is a teratogen, but its reproductive and developmental effects are poorly understood. A one-generation reproductive toxicity study was conducted with groups of 16 male and 16 female Fischer rats exposed to 0, 0.026, 0.064, 0.16, 0.4 or 1.0 mg OTA/kg in diet. Dams exposed to 1.0 mg OTA/kg diet had statistically significant F1 pup losses between implantation and postnatal day (PND 4). Delays in preputial separation (PPS) and vaginal opening (VO) were indicative of delayed puberty in F1 rats. Mild renal lesions in nursing pups indicated that exposure prior to weaning impacted the kidneys. The developing kidney was more susceptible to OTA than the adult kidney. Significant increases in multi-oocyte follicles (MOFs) and proportional changes in resting and growing follicles were observed in F1 female ovaries. Plasma testosterone was reduced in F0 males, and there were negative effects on sperm quality in F0 and F1 male rats. The results confirm that continuous dietary exposure to OTA causes post-implantation fetotoxicity in dams, and renal and reproductive toxicity in their male and female offspring.

Non-cytotoxic dosage of fumonisin B1 aggravates ochratoxin A-induced nephrocytotoxicity and apoptosis via ROS-dependent JNK/MAPK signaling pathway.

Ochratoxin A (OTA) and fumonisin B1 (FB1), two of the most toxicologically important mycotoxins, often coexist in a variety of foodstuff and feed in humans and animals. Because of the low content of FB1 in foodstuff and feed, alone harmfulness of FB1 is often ignored. However, it is unknown whether the lower dosage of FB1 aggravates the toxicity of other mycotoxins. In this article, we aimed to investigate the effects of the lower dosage of FB1 on OTA-induced nephrotoxicity and apoptosis, and its underlying mechanism in porcine kidney cells (PK-15). Our current study showed that the non-cytotoxic concentration of FB1 (8 µM) could enhance OTA(5 µM)-induced nephrocytotoxicity and the expression of pro-apoptosis-associated genes in PK-15 cells. We also observed that the production of reactive oxygen species (ROS) was increased. However, the expression of pro-apoptosis-associated genes were down-regulated when the N-acetylcysteine (NAC), a ROS scavenger, was used in our experiment. Besides, we found that the combined toxins could increase the protein expression of p-JNK instead of p-p38 and p-ERK. Pretreatment with SP600125, a JNK inhibitor, could significantly block the promotion effects of FB1 on OTA-induced nephrocytotoxicity and apoptosis. The protein expression of p-JNK was also inhibited and the promotion effects of FB1 were significantly alleviated when NAC was used. In conclusion, the non-cytotoxic dosage of FB1 could aggravate the nephrocytotoxicity and apoptosis caused by OTA via ROS-dependent JNK/MAPK signaling pathway.

Oral subchronic exposure to the mycotoxin ochratoxin A induces key pathological features of Parkinson's disease in mice six months after the end of the treatment.

Some epidemiological studies with different levels of evidence have pointed to a higher risk of Parkinson's disease (PD) after exposure to environmental toxicants. A practically unexplored potential etiological factor is a group of naturally-occurring fungal secondary metabolites called mycotoxins. The mycotoxin ochratoxin A (OTA) has been reported to be neurotoxic in mice. To further identify if OTA exposure could have a role in PD pathology, Balb/c mice were orally treated with OTA (0.21, 0.5 mg/kg bw) four weeks and left for six months under normal diet. Effects of OTA on the onset, progression of alpha-synuclein pathology and development of motor deficits were evaluated. Immunohistochemical and biochemical analyses showed that oral subchronic OTA treatment induced loss of striatal dopaminergic innervation and dopaminergic cell dysfunction responsible for motor impairments. Phosphorylated alpha-synuclein levels were increased in gut and brain. LAMP-2A protein was decreased in tissues showing alpha-synuclein pathology. Cell cultures exposed to OTA exhibited decreased LAMP-2A protein, impairment of chaperone-mediated autophagy and decreased alpha-synuclein turnover which was linked to miRNAs deregulation, all reminiscent of PD. These results support the hypothesis that oral exposure to low OTA doses in mice can lead to biochemical and pathological changes reported in PD.

Ochratoxin A induces nephrotoxicity in vitro and in vivo via pyroptosis.

Ochratoxin A (OTA), a prevalent nephrotoxic mycotoxin contaminant in food and feedstuff, has been reported to induce renal injury. To disclose the nephrotoxicity of continuous administration of OTA and to investigate potential mechanisms related to pyroptosis, male C57BL/6 mice were intraperitoneally injected with 1.0 and 2.0 mg/kg B.W. OTA every other day for 14 days. At 2.0 mg/kg B.W. OTA administration significantly increased histological injury and renal fibrosis molecules (α-SMA, Vimentin, TGF-ß) and activated the NOD-like receptor protein 3 (NLRP3) inflammasome and induced pyroptosis compared with control. In the in vitro tests, Madin-Darby canine kidney (MDCK) epithelial cells were exposed to 0-4.0 µg/ml OTA for 24 h in serum-free medium. Data showed that OTA dose-dependently affected cell viability and significantly up-regulated renal fibrosis genes (α-SMA, Vimentin, TGF-ß). 2.0 µg/ml OTA significantly induced NLRP3 inflammasome activation and caspase-1-dependent pyroptosis, increasing the expression and secretion of pro-inflammatory cytokines (IL-6, TNF-α) and pyroptosis-related genes (GSDMD, IL-1ß, IL-18) in MDCK cells. These outcomes were significantly abrogated after inhibiting NLRP3 activation with inhibitor MCC950 and silencing NLRP3 with small interfering RNA (siRNA). Furthermore, knockdown of caspase-1 also ameliorated OTA-induced renal fibrosis via the inhibition of pyroptosis. Collectively, the chosen doses of OTA-triggered nephrotoxicity through NLRP3 inflammasome activation and caspase-1-dependent pyroptosis both in vitro and in vivo.

Oral Sub-chronic Ochratoxin A Exposure Induces Gut Microbiota Alterations in Mice.

Gut microbiota plays crucial roles in maintaining host health. External factors, such as diet, medicines, and environmental toxins, influence the composition of gut microbiota. Ochratoxin A (OTA) is one of the most prevalent and relevant mycotoxins and is a highly abundant food and animal feed contaminant. In the present study, we aimed to investigate OTA gut microbiome toxicity in mice sub-chronically exposed to low doses of OTA (0.21, 0.5, and 1.5 mg/kg body weight) by daily oral gavage for 28 days. Fecal microbiota from control and OTA-treated mice was analyzed using 16S ribosomal RNA (rRNA) gene sequencing followed by metagenomics. OTA exposure caused marked changes in gut microbial community structure, including the decrease in the diversity of fecal microbiota and the relative abundance of Firmicutes, as well as the increase in the relative abundance of Bacteroidetes at the phylum level. At the family level, six bacterial families (unclassified Bacteroidales, Porphyromonadaceae, unclassified Cyanobacteria, Streptococcaceae, Enterobacteriaceae, Ruminococcaceae) were significantly altered by OTA exposure. Interestingly, OTA-induced changes were observed in the lower-dose OTA groups, while high-dose OTA group microbiota was similar to control group. Our results demonstrated that sub-chronic exposure at low doses of OTA alters the structure and diversity of the gut microbial community.

Dietary exposure assessment and risk characterization of citrinin and ochratoxin A in Belgium.

Exposure to mycotoxins is a worldwide problem. To ensure public health, it is imperative to characterize the risks related to these toxins. The present study aims to conduct a dietary exposure assessment of citrinin (CIT) and ochratoxin A (OTA) in the Belgian population using consumption data of a variety of foodstuffs. A total of 367 food samples from different food categories were collected in Belgian supermarkets and analysed for CIT and OTA using a validated liquid chromatography-tandem mass spectrometry method. Daily CIT and OTA exposure to the Belgian population was calculated based on the analytical results and food consumption data in three age categories (3-9, 10-17 and 18-64 years), obtained from a national food consumption survey. Furthermore, a risk characterization was performed for CIT, in which no intake values exceeded the tolerable daily intake (TDI) of 200 ng kg-1 bw day-1, indicating no health risk. However, a CIT intake level of 187 ng kg-1 bw day-1 was detected for children in the age category of 3-9 years in the worst case scenario for rice, indicating that rice consumption could contain a potential health hazard for young children. For OTA, a potential health risk was detected in several food categories (biscuits, croissants, rice, flour, meat imitates, herbs and spices) in the higher percentiles (P99) or at maximum found concentrations when calculating the margin of exposure (MoE) for neoplastic effects. An attempt to perform a cumulative health risk assessment for both toxins was done. Although a high number of uncertainties is involved, combined margin of exposure (MoET) values indicated a potential health risk related to the combined exposure to CIT and OTA. For the first time, our study demonstrated the potential health risks of CIT and OTA after individual and combined exposure, in particular related to rice consumption. Moreover, further research is recommended concerning multiple mycotoxin exposure in young children.

Subchronic exposure to individual and combined ochratoxin A and citrinin affects the expression of rat renal organic anion transporters.

Ochratoxin A (OTA) and citrinin (CIT) are mycotoxins known to co-contaminate human/animal food/feed. Their prominent nephrotoxic effects pose a threat to human and animal health. Studies have shown synergistic or additive effects of these two mycotoxins, but a clear consensus on this phenomenon does not exist. In vitro/vivo studies on OTA and CIT effects showed they elevate oxidative stress parameters. Some in vitro studies tested resveratrol (RSV) as a potential antioxidant to counteract these OTA and CIT effects. However, data on the combined effects of OTA + CIT mycotoxins and RSV on their in vivo toxicity is lacking. We used immunofluorescence microscopy and Western blotting to study the subchronic effects of individual/combined OTA (0.125 and 0.250 mg kg-1 b.w.) and CIT (20 mg kg-1 b.w.) on the localization/expression of rat renal organic anion transporters (rOats) (rOat1/Slc22a6, rOat2/Slc22a7, rOat3/Slc22a8, rOat5/Slc22a19) that mediate the secretion/reabsorption of organic anions in kidney proximal tubules. We investigated if RSV (20 mg kg-1 b.w.) can counteract the effects of both mycotoxins on the localization/expression of studied transporters. Results revealed Oat- and dose-dependent changes in protein expression of rOats. When combined with both mycotoxins, RSV decreased the protein expression of all of the studied rOats. Its effect was additive on Oat1/2/5. Thus, RSV failed to ameliorate OTA- and/or CIT-related nephrotoxic effects on the expression of studied rOats in rat kidneys.

Ochratoxin A induces glomerular injury through activating the ERK/NF-κB signaling pathway.

Ochratoxin A (OTA) was reported to induce proximal tubules nephrotoxicity in humans and animals. However, the toxicity of OTA on glomeruli has rarely been studied. We investigated OTA-induced glomerular injury and the underlying mechanisms. Mice were intraperitoneally treated with OTA (0, 0.5, 1.5 and 2.5 mg/kg b.w.) on alternate day for 3 weeks. OTA exposure decreased the weight gain ratio, the kidney index and increased the levels of serum creatinine and blood urea nitrogen. It induced also fragmentation and atrophy in glomeruli, and increased the expression of TNF-α, IL-6, COX-2, TGF-ß, α-SMA and vimentin in a dose-dependent manner. Human mesangial cells (HMC) were treated with OTA (0-8 µM) for 48 h. Treatment of HMC cells with OTA increased cell inhibition rate, up-regulated the expression of IL-6, TGF-ß, α-SMA and vimentin in a dose-dependent manner. Additionally, it enhanced the phosphorylation of ERK1/2 and p65, degradation of IκB-α and translocation of p65 into the nucleus. OTA-induced toxicity was attenuated by NF-κB and ERK1/2 inhibitors. In conclusion, these results suggest that OTA exposure induces glomerular injury via activation of the ERK/NF-κB signaling pathway, and provide novel insights into the research of OTA induced nephrotoxicity.

Impact of dietary Trichosporon mycotoxinivorans on ochratoxin A induced immunotoxicity; In vivo study.

Ochratoxin A (OA), the secondary metabolite of certain Aspergillus and Penicillium species, is one of the potent biological immune-suppressor. The present study was designed to explore the in-vivo efficacy of Trichosporon mycotoxinivorans (TR); yeast strain isolated from the hindgut of the termite Mastotermes darwiniensis, against the immunotoxicity of OA in broiler birds. For this purpose, broiler chicks were offered diet added with TR (0.5, 1.0 or 2.0 g/kg feed) and/or OA (0.15, 0.3 or 1.0 mg/kg feed) for 42 days. Dietary OA at all levels, resulted in significant reduction (p ≤ 0.05) in the immune response of broiler birds as recorded by vacuolation and darkly stained pyknotic nuclei in bursa of Fabricius and thymus, humoral immune responses to sheep red blood cells (SRBC), in-vivo lymphoproliferative response to Phytohemagglutinin-P (PHA-P) and mononuclear phagocytic system function assay. Addition of TR in broiler diet significantly reduced (p ≤ 0.05) the immunotoxicity of OA at 0.15 and 0.30 mg/kg; however, against higher dietary level of OA (1.0 mg/kg), a partial protection was observed. Feeding TR alone had no immunomodulatory effect at any of tested level. Dietary addition of TR is proposed as an approach to combat the OA mediated immunological damages in broiler birds.

Long-Time Instead of Short-Time Exposure in Vitro and Administration in Vivo of Ochratoxin A Is Consistent in Immunosuppression.

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium, contaminating in a wide variety of foods and feeds. Mycotoxins, including OTA, could cause immunosuppression in almost all previous studies in vivo. However, the vast majority of results in vitro showed that mycotoxins caused immunostimulation. Why the results of studies in vitro are contrary to studies in vivo is unknown. Our study aims to explore the underlying reason and mechanism of the paradoxical effect. In this study, porcine alveolar macrophage cell line 3D4/21 was chosen as an in vitro model and treated with 1.0 µg/mL OTA for different times. Some indexes, such as expression of inflammatory cytokines, migration, phagocytosis, macrophage polarization, autophagy-related proteins, and Akt1 phosphorylation, were detected. The results showed that pro-inflammatory cytokine expression, migration, and phagocytosis were increased, with macrophage polarization to the M1 phenotype at 24 h of OTA exposure. Surprisedly, anti-inflammatory cytokine expression was increased, cell phagocytosis and migration were decreased, and macrophage polarization was switched from M1 to M2 at 72 h of OTA exposure. Furthermore, we found that long-time exposure of OTA also suppressed autophagy, and the autophagy activator blocked the OTA-induced immunosuppression. Phosphorylation of Akt1 plays a positive role in autophagy inhibition. In conclusion, long-time instead of short-time exposure of OTA in vitro induced immunosuppression. The immunosuppression mechanism of OTA in vitro involved inhibition of autophagy through upregulating p-Akt1. Our results provide new insight into research on the mechanism of mycotoxin-induced immunosuppression in vitro.

Combined Inhibitory Effects of Citrinin, Ochratoxin-A, and T-2 Toxin on Aquaporin-2.

Aquaporins form a large family of transmembrane protein channel that facilitates selective and fast water transport across the cell membrane. The inhibition of aquaporin channels leads to many water-related diseases such as nephrogenic diabetes insipidus, edema, cardiac arrest, and stroke. Herein, we report the molecular mechanism of mycotoxins (citrinin, ochratoxin-A, and T-2 mycotoxin) inhibition of aquaporin-2 (AQP2) and arginine vasopressin receptor 2. Molecular docking, molecular dynamics simulations, quantum chemical calculations, residue conservation-coupling analysis, sequence alignment, and in vivo studies were utilized to explore the binding interactions between the mycotoxins and aquaporin-2. Theoretical studies revealed that the electrostatic interactions induced by the toxins pulled the key residues (187Arg, 48Phe, 172His, and 181Cys) inward, hence reduced the pore diameter and water permeation. The permeability coefficient of the channel was reduced from native ((3.32 ± 0.75) × 10-14 cm3/s) to toxin-treated AQP2 ((1.08 ± 0.03) × 10-14 cm3/s). The hydrogen bonds interruption and formation of more hydrogen bonds with toxins also led to the reduced number of water permeation. Further, in vivo studies showed renal damages and altered level of aquaporin expression in mycotoxin-treated Mus musculus. Furthermore, the multiple sequence alignments among the model organism along with evolutionary coupling analysis provided the information about the interdependences of the residues in the channel.

Precision toxicology shows that troxerutin alleviates ochratoxin A-induced renal lipotoxicity.

Lipotoxicity is the most common cause of severe kidney disease, with few treatment options available today. Precision toxicology can improve detection of subtle intracellular changes in response to exogenous substrates; thus, it facilitates in-depth research on bioactive molecules that may interfere with the onset of certain diseases. In the current study, troxerutin significantly relieved nephrotoxicity, increased endurance, and improved systemic energy metabolism and renal inflammation in OTA-induced nephrotic mice. Lipidomics showed that troxerutin effectively reduced the levels of triglycerides, phosphatidylcholines, and phosphatidylethanolamines in nephropathy. The mechanism was partly attributable to troxerutin in alleviating the aberrantly up-regulated expression of sphingomyelinase, the cystic fibrosis transmembrane conductance regulator, and chloride channel 2. Renal tubular epithelial cells, the main site of toxin-induced accumulation of lipids in the kidney, were subjected to transcriptomic profiling, which uncovered several metabolic factors relevant to aberrant lipid and lipoprotein metabolism. Our work provides new insights into the molecular features of toxin-induced lipotoxicity in renal tubular epithelial cells in vivo and demonstrates the function of troxerutin in alleviating OTA-induced nephrosis and associated systemic energy metabolism disorders.-Yang, X., Xu, W., Huang, K., Zhang, B., Wang, H., Zhang, X., Gong, L., Luo, Y., He, X. Precision toxicology shows that troxerutin alleviates ochratoxin A-induced renal lipotoxicity.

Renal toxicity through AhR, PXR, and Nrf2 signaling pathway activation of ochratoxin A-induced oxidative stress in kidney cells.

Because ochratoxin A (OTA) is widely found in foods, people are susceptible to OTA exposure. The mechanism leading to renal toxicity induced by OTA remains unclear. The aim of this study was to investigate OTA-induced toxicity in human proximal tubule HK-2 cells. OTA decreased cell viability, and the expression of kidney injury molecule-1 (KIM-1), a kidney damage marker, was increased when HK-2 cells were exposed to OTA. Additionally, OTA treatment of cells increased intracellular reactive oxygen species and malondialdehyde and decreased glutathione levels. OTA-treated cells induced the aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) genes followed by induction of the cytochrome P450 1A1 (CYP1A1), CYP1A2, and CYP3A4 genes representing phase I enzyme. The mRNA expression of phase II enzymes such as heme oxygenase-1, nicotinamide adenine dinucleotide phosphate-quinone oxidoreductase 1, and glutamate cysteine ligase catalytic subunit were upregulated by activation of NF-E2-related factor 2 (Nrf2) translocation by treatment with OTA. The response of OTA-orally administered mice also showed marked increases in these enzymes as well as KIM-1. These results indicate that OTA induces phase I and II enzymes through the AhR, PXR, and Nrf2 signaling pathways in HK-2 cells, which may lead to modulation of proximal tubule injury.

Ochratoxin A induces cytoprotective autophagy via blocking AKT/mTOR signaling pathway in PK-15 cells.

Ochratoxin A (OTA) could cause a variety of toxicological effects especially nephrotoxicity in animals and humans. Autophagy is a highly conserved metabolic process that plays an important role in the maintenance of cellular homeostasis under stress. However, the role of autophagy in OTA-induced nephrotoxicity is unknown. In the present study, we demonstrated that OTA treatment at 2.0-8.0 µM could increase cytotoxicity of PK-15 cells by inducing apoptosis as shown by the increased Annexin V/PI staining, increased caspase-3 and PARP cleavage and increased apoptotic nuclei. Meantime, autophagy was triggered when OTA was administrated, as indicated by markedly increased expressions of LC3-II, ATG5 and Beclin-1, accumulation of GFP-LC3 dots and increased double- or single-membrane vesicles. OTA treatment decreased p-AKT and p-mTOR activities, and OTA-induced autophagy was inhibited when insulin was applied. Furthermore, OTA treatments with autophagy inhibitors (3-methyladenine or chloroquine) or knockdown of autophagy-related genes (ATG5 or Beclin-1) resulted in significantly reduced autophagy level and enhanced cytotoxicity. In conclusion, OTA induces cytoprotective autophagy against its cytotoxicity and inactivation of AKT/mTOR axis plays a critical role in autophagy induction.

Effects of dietary deoxynivalenol or ochratoxin A on performance and selected health indices in Atlantic salmon (Salmo salar).

Post-smolt Atlantic salmon (Salmo salar) were fed with standard feed added one of five concentrations of either pure deoxynivalenol (DON; 0.5-6 mg/kg) or pure ochratoxin A (OTA; 0.2-2.4 mg/kg), or no added toxins for up to 8 weeks. Performance effects (feed intake, feed efficiency, gain, length and condition factor), various clinical biochemical parameters, packed cell volume and vaccination response against Aeromonas salmonicidae were all inversely correlated with DON dose, whereas relative liver weight increased with DON dose. In fish fed OTA, however, the effects at the doses tested were rather small. We observed no effects of OTA exposure on performance parameters, but some clinical biochemical parameters tended to increase with OTA dose primarily at 3 weeks, and compared with controls OTA exposure caused increased mRNA expression of two immune markers in the spleen. No liver histopathological effects were found from DON or OTA exposure. For DON, we derived a BMDL20 of 0.3 mg/kg feed for reduced total protein in plasma, a BMDL5 of 0.5 mg/kg feed for reduced condition factor, and a NOAEL of 1 mg/kg feed for DON. For OTA, a BMDL or NOAEL could not be derived (>2.4 mg/kg).

A reproductive and developmental screening study of the fungal toxin ochratoxin A in Fischer rats.

The presence of the mycotoxin ochratoxin A (OTA) in cereal grains is due to the growth of toxigenic Penicillium mold on stored crops. Human exposure to OTA is higher in infants, toddlers, and children than in adolescents and adults, based on exposure assessments of ng OTA consumed/kg body weight/day. Ochratoxin A is nephrotoxic and teratogenic in animals, but its effects on juveniles exposed during the reproduction and development period have not been studied. To address this, Fischer rats were exposed to 0, 0.16, 0.4, 1.0, or 2.5 mg OTA/kg diet throughout breeding, gestation, and lactation and its adverse effects were assessed in adult rats and their offspring on postnatal day (PND) 21. There were no effects on implantation but post-implantation fetotoxicity was observed in the 2.5 mg/kg dose group, corresponding to a calculated dose of 167.0 µg/kg bw/day in dams. Adverse effects on body and kidney weights and on clinical parameters indicative of renal toxicity were significant in adult rats exposed to 1.0 mg OTA/kg diet (55.2 and 73.3 µg/kg bw/day in adult males and females, respectively) and in PND21 rats at the 0.4 mg/kg dose (33.9 µg/kg bw/day in dams), suggesting that weanling rats were more sensitive to OTA than adults. Overall, nephrotoxicity was the primary effect of OTA in weanling rats exposed throughout gestation and lactation at sub-fetotoxic concentrations in diet.

Combination of Selenomethionine and N-Acetylcysteine Alleviates the Joint Toxicities of Aflatoxin B1 and Ochratoxin A by ERK MAPK Signal Pathway in Porcine Alveolar Macrophages.

Our previous studies showed that aflatoxin B1 (AFB1) and ochratoxin A (OTA) could trigger joint immune toxicity. Little is known about the combined effects of selenomethionine (SeMet) and N-acetylcysteine (NAC) on the joint toxicities of the two toxins. In this study, results showed that SeMet or NAC alone or in combination significantly alleviated the downswing of cell viability, glutathione production, and phagorytosis induced by AFB1 and OTA in porcine alveolar macrophages. The uptrend of lactate dehydrogenase activities, apoptosis, reactive oxygen species levels, and the relative mRNA of inflammatory cytokines triggered by the two toxins was decreased. Combination of them was more effective than single application. Knockdown of p38, c-JUN N-terminal kinase (JNK), or extracellular signal-regulated kinase (ERK) via use of the corresponding specific siRNA could alleviate the joint toxicities of AFB1 and OTA. However, the ERK but not p38 or JNK pathway was involved in the protection of SeMet and NAC against the immunotoxicity. In conclusion, combination of SeMet and NAC might be a new therapeutic orientation for preventing the joint toxicities induced by AFB1 and OTA.

Effects of feeding bentonite clay upon ochratoxin A-induced immunosuppression in broiler chicks.

A presence of mycotoxins in feed is one of the most alarming issues in the poultry feed industry. Ochratoxins, produced by several Aspergillus and Penicillium species, are important mycotoxin regarding the health status of poultry birds. Ochratoxins are further classified into to several subtypes (A, B, C, etc) depending on their chemical structures, but ochratoxin A (OTA) is considered the most important and toxic. Bentonite clay, belonging to phyllosilicates and formed from weathering of volcanic ashes, has adsorbent ability for several mycotoxins. The present study was designed to study the effects of bentonite clay upon OTA-induced immunosuppression in broiler chicks. For this, 480 day-old broiler chicks were procured from a local hatchery and then different combinations of OTA (0.15, 0.3, or 1.0 mg/kg) and bentonite clay (5, 10, and 20 g/kg) were incorporated into their feed. At 13, 30, and 42 days of age, parameters such as antibody responses to sheep red blood cells, in situ lymphoproliferative responses to mitogen (PHA-P), and in situ phagocytic activity (i.e., via carbon clearance) were determined respectively. The results indicated there was a significant reduction of total antibody and immunoglobulin titres, lymphoproliferative responses, and phagocytic potential in OTA-treated birds, suggesting clear immunosuppression by OTA in birds in a dose-dependent manner. These results were also significantly lower in all combination groups (OTA with bentonite clay), suggesting few to no effects of feeding bentonite clay upon OTA- induced alterations in different immune parameters.

Sex differences in ochratoxin a toxicity in F344 rats after 7 and 21 days of daily oral administration.

Ochratoxin A (OTA) is a potent renal carcinogen in male rats but not in females. The mechanisms underlying these differences are unknown. The sex-dependent response of F344 rats after a repeated OTA oral administration for 7 (0.50 mg/kg bw) or 21 days (0.21 and 0.50 mg/kg bw) was evaluated. General toxicity, sex and thyroid hormones and histopathology were studied. OTA was quantified (HPLC-FLD) in plasma, kidney and liver and the expression of kidney transporters (RT-qPCR) was studied. After 7 days, kidney histopathology showed more pronounced signs of toxicity in males than in females. After 21 days, a higher toxicity was observed but sex differences disappeared. OTA concentration in plasma and tissues was similar in both sexes. Downregulation was the general OTA-induced effect. Oats' downregulation was slow in males and Oat3 did not change in females. Oatp1 was strongly downregulated in males after 21 days. An opposite effect was observed in Bcrp after 21 days: downregulation in males and upregulation in females. Females showed a dose- and time-dependent decrease of progesterone. Despite the sex differences, the final balance in OTA toxicokinetics at renal cell level does not seem to support a higher accumulation of OTA in male kidneys.

Comparative effect of ochratoxin A on inflammation and oxidative stress parameters in gut and kidney of piglets.

Ochratoxin A (OTA) is a secondary metabolite produced by fungi of Aspergillus and Penicillium genra. OTA is mainly nephrotoxic but can also cause hepatotoxicity, mutagenicity, teratogenicity, neurotoxicity and immunotoxicity. As recent studies have highlighted the close relationship between gastrointestinal tract and kidney, as principal organs involved in absorption and respective excretion of xenobiotics, the aim of the present study was to analyze the effect of a subchronic exposure (30 days) to 0.05 mg/kg OTA on immune response and oxidative stress parameters at the level of intestine and kidney of young swine. The experiment was realised on twelve crossbred weaned piglets randomly allotted to both control group or toxin group fed 0.050 mg OTA/kg feed. Our results have shown that a subchronic intoxication with a low dose of OTA for 30 days affected the immune response and the anti-oxidant self-defense at gut and kidney level. The gene expression of both markers of signaling pathways involved in inflammation and inflammatory cytokines were affected in a much higher extent in the gut than in the kidney Of OTA intoxicated piglets.