Cytotoxic and inflammatory effects of individual and combined exposure of HepG2 cells to zearalenone and its metabolites.

Zearalenone (ZEA), a mycotoxin produced by several Fusarium spp., is most commonly found as a contaminant in stored grain. ZEA derivatives (α-zearalenol (α-ZOL), ß-zearalenol (ß-ZOL)) can also be produced by Fusarium spp. in corn stems infected by fungi in the field. Also, following oral exposure, zearalenone is metabolized in various tissues, particularly in the liver, the major metabolites being α-ZOL and ß-ZOL. The co-exposure of cells to mixture of a combination of mycotoxins may cause an increase of toxicity produced by these mycotoxins. In this in vitro study, we investigated the combined effects of ZEA, α-ZOL, ß-ZOL in binary mixtures on the viability and inflammatory response of human liver cancer cell line (HepG2). Cell viability was assessed after 72 h using a neutral red assay. Effect of the toxins and their binary combinations on the expression of genes involved in inflammation (IL-1ß, TNF-α, and IL-8) were assessed through qPCR. Our viability data showed that irrespective of the toxin combinations, the toxins have synergistic effect. ZEA + α-ZOL and ZEA + ß-ZOL mixtures have induced a slight to high antagonistic response on inflammatory cytokines at low concentrations that have turned into strong synergism for high concentrations. α-ZOL + ß-ZOL showed antagonistic effects on inflammation for IL-1ß and TNF-α, but act synergic for IL-8 at high toxin concentrations. This study clearly shows that co-contamination of food and feed with ZEA metabolites should be taken into consideration, as the co-exposure to mycotoxins might result in stronger adverse effect than resulted from the exposure to individual toxin.

A comparison between the effects of ochratoxin A and aristolochic acid on the inflammation and oxidative stress in the liver and kidney of weanling piglets.

Ochratoxin A (OTA) and aristolochic acid (AA) are toxins that can frequently contaminate cereals and cereals-based products. The present study has realized a comparison between the effect of OTA and AA on oxidative stress and inflammation in both the liver and kidney of pigs as major organs involved in the metabolism of xenobiotics. Fifteen pigs (five pigs/group) were randomly distributed in three groups (control, OTA, and AA) and were fed diets contaminated or not with 250 µg toxin/kg for 28 days. Consumption of a diet contaminated with OTA and AA increase the concentration of serum creatinine as compared with the control group. The exposure of piglets to AA decrease the activity of enzymes involved in the oxidative stress response: catalase (CAT), superoxide dismutase (SOD), and glutathione peroxydase (GPx) in the liver and kidney while OTA decrease only GPx activity and only in the kidney. The consumption of the diets contaminated with AA increase in the liver the synthesis of tumor necrosis factor (TNF) alpha, interferon (IFN) gamma, Interleukin (IL)-1 beta, IL-6, and IL-8 synthesis, while IL-4 was increase by OTA and decreased by AA. In the kidney, AA increase the TNF alpha and IFN gamma synthesis as compared with the control. In conclusion, our results have shown that beside the alteration of serum markers, much known indicators for nephropathy, OTA and AA can induce inflammation and oxidative stress. In conclusion, the inflammatory effects were more pronounced for AA and at the liver level, while oxidative stress was induced both in the liver and kidney.

Assessment of the effect of grape seed cake inclusion in the diet of healthy fattening-finishing pigs.

Modulatory capacity of bioactive compounds from different wastes has been scarcely investigated in pigs. This study aimed to evaluate the effects of dietary inclusion of grape seed cakes (GS diet) on performance and plasma biochemistry parameters as health indicators, as well as on several markers related to inflammation and antioxidant defence in the liver of fattening-finishing pigs. Twelve cross-bred pigs (TOPIG) were randomly assigned to one of two experimental diets: control and 5% grape seed cake diet during finishing period (24 days). No effect of GS diet on pig performance and blood biochemistry was observed. However, GS diet decreased significantly (-9.05%, p < .05) the cholesterol concentration (85.71 ± 0.94 mg/dl vs 94.24 ± 2.16 mg/dl) and increased IgA level (+49.90%, p < .05) in plasma (5.04 ± 0.5 mg/ml vs 3.36 ± 0.7 mg/ml). GS cakes decreased the inflammatory response in the liver of pigs fed with GS diet by lowering the Gene expression and protein concentration of pro-inflammatory cytokines (IL-1ß, IL-8, TNF-α and IFN-γ) as well as the mRNA abundances of NF-κB signalling molecules. The antioxidant status was not increased by GS diet. The gene expression and activity of catalase decreased significantly. The gene expression of Nrf2, superoxide dismutase, glutathione peroxidase and heat-shock protein decreased, and no effect on their activity was observed with the exception of catalase activity which decreased. However, TBARS was reduced significantly. GS diet showed a modulatory effect on antioxidative status as well as anti-inflammatory and hypocholesterolic properties without effect on pig performance.

Immunotoxicological risk of mycotoxins for domestic animals.

Mycotoxins are a group of structurally diverse fungal secondary metabolites that elicit a wide spectrum of toxicological effects. Of particular interest is the capacity of some mycotoxins to alter normal immune function when present in food at levels below observable overt toxicity. The sensitivity of the immune system to mycotoxin-induced immunosuppression arises from the vulnerability of the continually proliferating and differentiating cells that participate in immune-mediated activities and regulate the complex communication network between cellular and humoral components. Mycotoxin-induced immunosuppression may be manifested as depressed T- or B-lymphocyte activity, suppressed antibody production and impaired macrophage/neutrophil-effector functions. The immune system is primarily responsible for defence against invading organisms. Suppressed immune function by mycotoxins may eventually decrease resistance to infectious diseases, reactivate chronic infections and/or decrease vaccine and drug efficacy.

Changes in performance, blood parameters, humoral and cellular immune responses in weanling piglets exposed to low doses of aflatoxin.

A feeding trial was conducted to evaluate the effect of aflatoxin (AF)-contaminated diets on growth and hematological and immunological parameters. Low doses of aflatoxins (140 and 280 ppb) were included in a corn-soybean diet provided for ad libitum consumption to 36 weanling piglets for a period of 4 wk. A "dose-related" decrease in weight gain was observed in treated animals. This effect was significant (P < 0.05) in the 280 ppb-treated group compared to the control group. Ingestion of AF-contaminated feed at either level had no effect on total red blood cell numbers or on their relative number of lymphocytes, monocytes, neutrophils, basophils, and eosinophils in blood. Likewise, AF did not alter globulin, albumins, or total protein concentrations in serum, nor did AF alter the expression of regulatory cytokines produced by either Th1 (IL-2) or Th2 (IL-4) lymphocyte subsets in phytohemagglutinin-stimulated blood samples. By contrast, AF had a biphasic effect on total white blood cell number; the low dose of AF (140 ppb) decreased the total number of white blood cells, whereas the high dose (280 ppb) had the opposite effect. Consumption of AF also increased the concentration of gamma-globulin in the serum. A reduced immune response induced by Mycoplasma agalactiae in the 280-ppb-treated group was also observed. Cytokine mRNA expression in phytohemagglutinin-stimulated blood cells indicated that AF decreased proinflammatory (IL-1beta, TNF-alpha) and increased anti-inflammatory (IL-10) cytokine mRNA expression. These results demonstrate that low doses of AF depress growth and alter many aspects of humoral and cellular immunity in pigs.