No abstract

The toxicity of zearalenone (ZEA) was evaluated in swine spleen, a key organ for the innate and adaptative immune response. Weaned pigs were fed for 18 days with a control or a ZEA contaminated diet. The effect of ZEA was assessed on wide genome expression, pro- (TNF-α, IL-8, IL-6, IL-1β, IFN-γ) and anti-inflammatory (IL-10, IL-4) cytokines, other molecules involved in inflammatory processes (MMPs/TIMPs), as well as signaling molecules, (p38/JNK1/JNK2-MAPKs) and nuclear receptors (PPARγ/NFkB/AP-1/STAT3/c-JUN). Microarray analysis showed that 46% of total number of differentially expressed genes was involved in cellular signaling pathway, 13% in cytokine network and 10% in the inflammatory response. ZEA increased expression and synthesis of pro- inflammatory (TNF-α, IL-8, IL-6, IL-1β) and had no effect on IFN-γ, IL-4 and IL-10 cytokines in spleen. The inflammatory stimulation might be a consequence of JNK pathway activation rather than of p-38MAPK and NF-kB involvement whose gene and protein expression were suppressed by ZEA action. In summary, our findings indicated the role of ZEA as an immune disruptor at spleen level.

Zearalenone (ZEA) is an oestrogenic mycotoxin produced by Fusarium species, considered to be a risk factor from both public health and agricultural perspectives. In the present in vivo study, a feeding trial was conducted to evaluate the in vivo effect of a ZEA-contaminated diet on immune response in young pigs. The effect of ZEA on pro-inflammatory (TNF-a, IL-8, IL-6, IL-1b and interferon-g) and antiinflammatory (IL-10 and IL-4) cytokines and other molecules involved in inflammatory processes (matrix metalloproteinases (MMP)/ tissue inhibitors of matrix metalloproteinases (TIMP), nuclear receptors: PPARg and NF-kB1, mitogen-activated protein kinases (MAPK): mitogen-activated protein kinase kinase kinase 7 (TAK1)/mitogen-activated protein kinase 14 (p38a)/mitogen-activated protein kinase 8 ( JNK1)/ mitogen-activated protein kinase 9 ( JNK2)) in the liver of piglets was investigated. The present results showed that a concentration of 316 parts per billion ZEA leads to a significant decrease in the levels of pro-and anti-inflammatory cytokines at both gene expression and protein levels, correlated with a decrease in the levels of other inflammatory mediators, MMP and TIMP. The results also showed that dietary ZEA induces a dramatic reduction in the expressions of NF-kB1 and TAK1/p38a MAPK genes in the liver of the experimentally intoxicated piglets, and has no effect on the expression of PPARg mRNA. The present results suggest that the toxic action of ZEA begins in the upstream of the MAPK signalling pathway by the inhibition of TAK1, a MAPK/NF-kB activator. In conclusion, the present study shows that ZEA alters several important parameters of the hepatic cellular immune response. From an economic point of view, these data suggest that, in pigs, ZEA is not only a powerful oestrogenic mycotoxin but also a potential hepatotoxin when administered through the oral route. Therefore, the present results represent additional data from cellular and molecular levels that could be taken into account in the determination of the regulation limit of the tolerance to ZEA.

Ochratoxins, are toxic fungal metabolites produced by certain moulds of the genera Aspergillus and Penicillium that grow on a wide range of raw food commodities. The most relevant toxin is ochratoxin A (OTA) and the European Commission has established guidance values for OTA concerning complementary and complete feeding stuff recommending that for pigs a maximum concentration of 0.05 mg/kg. These guidance values represent only a recommendation of the Commission and the establishment of a legal regulation needs additional toxicological data generated from farm animal experiments. The aim of this paper was to investigate the effect of OTA – at the recommended EU guidance value of 0.05 mg/kg – on liver health. For this purpose, twelve crossbred, weaned piglets were fed for 33 days a maize-soybean-meal-based diet contaminated or not with 0.05 mg/kg OTA. Blood plasma samples were collected at the end of this period and subjected to biochemical analyses, whereas liver samples were analysed for cytokine concentration (ELISA), enzyme activity and expression of selected genes (qRT-PCR) involved in liver metabolism. Exposure to OTA resulted in a significant decrease in the concentrations of total protein, albumin and nitric oxide in plasma, and interleukin-6 in the liver. OTA exposure also resulted in a significant increase of alanine aminotransferase and triglycerides in plasma and of superoxide dismutase in the liver. In conclusion, the administration of 0.05 mg/kg of OTA, to weaned piglets for a period of 33 days caused measurable hepatocellular injury in the toxin-exposed. Additional in vivo studies should be performed with larger numbers of animals in order to confirm our results and to provide robust data for the establishment of safe concentrations of OTA in swine feeds.

Trichotecenes are mycotoxins produced by Fusarium sp., which may contaminate animal feeds and human food. A feeding trial was conducted to evaluate the effect of a fusarotoxin-contaminated diet, and to explore the counteracting potential of a calcium fructoborate (CFrB) additive on performance, typical health biochemistry parameters and immune response in weaned pigs. A naturally contaminated maize, containing low doses of deoxynivalenol, zearalenone, fumonisins and T-2/HT-2 toxins (1790, 20, 0·6 and 90 parts per billion), was included in a maize-soyabean meal diet, and given ad libitum to eight weaned piglets (two groups: four pigs/group) for a period of 24 d. CFrB was administered to one of the contaminated groups and to another four piglets as a daily supplement, following the manufacturer's recommendation. A decrease in performance was observed in contaminated animals at this concentration of feed toxins, which was ameliorated by the dietary CFrB supplementation. Fusarium toxins also altered the pig immune response by increasing (P, 0·05) the ex vivo peripheral blood mononuclear cell proliferation (111·7 % in comparison with control), the respiratory burst of porcine granulocytes (15·4 % for responsive cells v. 5·1 % for unstimulated cells and 70·95 v. 22·65 % for stimulated cells, respectively), the percentage of peripheral T, CD3þ CD4 þ and CD3 þ CD8 þ subsets and the synthesis of IL-1b, TNF-a and IL-8 (123·8, 217·1 and 255·1 %, respectively). The diet containing the CFrB additive reduced these exacerbated cellular immune responses induced by Fusarium toxins. However, consumption of CFrB did not counteract the effect of mycotoxins on biochemistry parameters, and increased plasma IgM and IgG of contaminated pigs.