Judit Szabó-Fodor

Individual and Combined Effects of Subchronic Exposure of Three Fusarium Toxins (Fumonisin B, Deoxynivalenol and Zearalenone) in Rabbit Bucks

Objective of the study was to determine reproductive toxicity of Fusarium toxins orally at three subchronic doses on adult Pannon White male rabbits. The four treatments were: control (C, toxin-free diet), F (5 mg/kg FB1), DZ (1 mg/kg DON+0.25 mg/kg ZEA), FDZ (5 mg/kg FB1+1 mg/kg DON+0.25 mg/kg ZEA) for 65 days (n=15/treatment). The doses were pre-determined according the EU limits in finished feed for young pig (in the absence of limits for rabbits’ feed; based on the European Commission Recommendation 2006/576/EC and the European Commission Directive 2003/100/EC). The most pronounced effects of the toxins were exerted on the reproductive processes. The ratio of spermatozoa showing progressive forward motility decreased (P<0.05) from 80% to 67% in the FDZ group by day 60. Differences were found between the groups DZ (66.3% ± 23.7) and C (80.2% ± 11.2) in spermatozoa morphology. GnRH treated animals produced less testosterone in FDZ animals, compared to the other three groups (P<0.05). In the comet assay the individual fumonisin treatment resulted in significantly less 0 comets (intact cells), compared to all others. Based on the prevalence of score, lower (P<0.0001) damage was observed in FDZ group, as compared to F and DZ. Among the mycotoxins studied, additive or less than additive effect was found in case of spermatogenesis and sperm cell morphology, synergism in testosterone production, while FB1 acted antagonistically against DON+ZEA in comet assay. All mycotoxins provoked moderate lipid-peroxidation, based on the changes of glutathione concentration, glutathione peroxidase activity and formation of malondialdehyde and conjugated dienes and trienes, and exerted slight genotoxicity based on comet assay, FB1 being antagonistic towards DON+ZEA. In F, DZ and FDZ animals the intensity of spermatogenesis decreased by 43, 31 and 64%, respectively, which was reflected by lack of differentiated spermatozoa, thinning of the germinal epithelium, the appearance of multinuclear giant cells, indicative of the disturbance of meiosis and mitosis of the germinal epithelial cells and in some cases the lack of spermatogonia.

Acute hepatic effects of low-dose fumonisin B1 in rats

Adult male Wistar rats were enrolled in a study to test the acute hepatic effects of 50 mg/kg fumonisin B1 in feed for 5 days. Fumonisin B1 depressed growth and feed intake, and absolute and relative liver weight showed a significant increase. The proportions of C17:0, C18:3 n3, C22:5 n3 and C22:6 n3 fatty acids decreased in the hepatic phospholipid fraction. All proportional decreases modified the hepatocellular membrane lipids into a more rigid state. The fatty acid profile modifications were partly compensated for by endogenous glutathione (preventing the formation of conjugated dienes and trienes as initial phase lipid peroxidation indicators), while the enzymatic antioxidant defence system (glutathione peroxidase) was unaltered. In contrast, hepatic malondialdehyde, the cytotoxic product of end-phase lipid peroxidation showed a concentration increase even after 5 days of feeding. The results indicate a rather strong and rapid hepatic effect of FB1, immediately impairing membrane phospholipids, even before the enzymatic antioxidant defence is activated.

Individual and Combined Effects of Fumonisin B1, Deoxynivalenol and Zearalenone on the Hepatic and Renal Membrane Lipid Integrity of Rats

(1) Background and (2) Methods: A 14-day in vivo, multitoxic (pure mycotoxins) rat experiment was conducted with zearalenone (ZEA; 15 μg/animal/day), deoxynivalenol (DON; 30 μg/animal/day) and fumonisin B1 (FB1; 150 μg/animal/day), as individual mycotoxins, binary (FD, FZ and DZ) and ternary combinations (FDZ), via gavage in 1 mL water boluses. (3) Results: Body weight was unaffected, while liver (ZEA↑ vs. DON) and kidney weight (ZEA↑ vs. FDZ) increased. Hepatocellular membrane lipid fatty acids (FAs) referred to ceramide synthesis disturbance (C20:0, C22:0), and decreased unsaturation (C22:5 n3 and unsat. index), mainly induced by DON and to a lesser extent by ZEA. The DON-FB1 interaction was additive on C20:0 in liver lipids. In renal phospholipids, ZEA had the strongest effect on the FA profile, affecting the saturated (C18:0) and many n6 FAs; ZEA was in an antagonistic relationship with FB1 (C18:0) or DON (C18:2 n6, C20:1 n9). Hepatic oxidative stress was the most expressed in FD (reduced glutathione and glutathione peroxidase), while the nephrotoxic effect was further supported by lipid peroxidation (malondialdehyde) in the DON treatment. (4) Conclusions: In vivo study results refer to multiple mycotoxin interactions on membrane FAs, antioxidants and lipid peroxidation compounds, needing further testing.

Preliminary results on the interactive effects of deoxynivalenol, zearalenone and fumonisin B1 on porcine lymphocytes

Fusarium mycotoxins, such as fumonisin B1 (FB1), deoxynivalenol (DON) and zearalenone (ZEN), frequently co-occur in feed raw materials and their presence is ubiquitous. The aims of this study were to determine the concentration that inhibits cell viability by 50% (IC50 values) for each mycotoxin (after 24, 48 and 72 h) and to investigate their combined effects in binary (DON + ZEN: DZ, DON + FB1: DF, FB1 + ZEN: FZ) and ternary (DFZ) mixtures using cyto- and genotoxicity on porcine lymphocytes as endpoints. The potency of cytotoxicity of the three toxins in an increasing order was FB1 < ZEN < DON. The range of IC values depending on the period of exposure was 0.31-0.42 μg/ml and 16.6- 22.9 μg/ml for DON and ZEN, respectively, and 101.15 μg/ml for FB1 (50% viability was reached only after 72 h). The main interaction observed was antagonism regarding cytotoxicity. Lower and higher sets of concentrations were used for the genotoxicity (comet assay) experiments. When lower concentrations were used, antagonism was again the main interaction observed. However, at higher concentrations an antagonism was confirmed only for DFZ, whereas for DZ and FZ a synergism was observed. Interactions of DF were inconsistent in different exposure periods in both series of experiments. Further studies with additional endpoints should be performed (e.g. DNA fragmentation, protein synthesis) in order to elucidate the mechanisms underlying the interactions observed.

Fumonisin B1 exposure increases Hsp70 expression in the lung and kidney of rats without inducing significant oxidative stress

The objective of this experiment was to determine whether fumonisin B1 (FB1) added to the diet of rats in a dose of 50 mg/kg changes the production of heat shock protein 70 (Hsp70) in the lungs and kidney of rats. We also studied the effect of this mycotoxin on the antioxidant system of the body. Mature (8 weeks old) male Wistar Crl:WI BR rats (n = 6/group) were fed the toxin-containing diet for 5 days. FB1 resulted in a 7% body weight reduction without significantly changing the feed intake. Western blot analysis of the lungs and kidney demonstrated a substantial (1.4-fold and 1.8-fold, respectively) increase in Hsp70 expression. Alterations could not be detected in the clinical chemical parameters (total protein, albumin, total cholesterol, glucose, creatinine and urea concentrations, and aspartate aminotransferase activity). There was no statistically significant change in malondialdehyde concentrations and the measured antioxidant parameters (the amount of reduced glutathione, GSH and glutathione peroxidase activity, GPx) in the blood plasma, lung and kidney tissue. Thus, it can be concluded that FB1 did not induce oxidative stress in the lungs and kidney, but increased Hsp70 production.

Physiological Effects of Whey- and Milk-Based Probiotic Yogurt in Rats

In an in vitro experiment commercially available probiotic products were tested for the survival of bacteria under conditions of simulated human digestion either when used alone or mixed into yogurt. In the in vivo experiment the effects of feeding a whey- and milk-based yogurt prepared with the probiotic strain showing adequate survival in the in vitro experiment, was measured on body weight, feed con¬sumption and immune response of rats (IgG and IgA level after immunisation), on the composition and volatile fatty acid production of the intestinal microbiota and on the structure of intestinal villi. The Lactobacillus acidophilus (LA-15) strain had inadequate surviving ability in rats. Bifidobacterium animalis ssp. lactis (BB-12) improved the composition of the intestinal microflora, whereas whey-containing product had a mild immunostimulating effect and exerted a favourable influence on the morphology of intestinal villi. The consumption of yogurts increased the depth of crypts in the ileum, which resulted in enhanced secretion and thus softer faeces.

Feed exposure to FB1 can aggravate pneumonic damages in pigs provoked by P. multocida

The possible interaction between Pasteurella multocida and the mycotoxin fumonisin B1 (FB1), recognised as one of the most often food/feed contaminant, was studied with the aim to evaluate whether and how FB1 can influence and/or complicate the development and severity of various pathological damages provoked by Pasteurella multocida in some internal organs of pigs. Heavier lung pathology was seen in pigs experimentally infected with Pasteurella multocida, when the same were exposed to 20ppm dietary levels of fumonisin B1 (FB1) as was assessed by gross pathology, pathomorphological examinations, clinical biochemistry and some immunological investigations. The most typical damages in FB1 treated pigs were the strong oedema in the lung and the slight oedema in the other internal organs and mild degenerative changes in the kidneys, whereas the typical pathomorphological findings in pigs infected with Pasteurella multocida was broncho-interstitial pneumonia. FB1 was found to aggravate pneumonic changes provoked by P. multocida in the cranial lobes of the lung and to complicate pneumonic damages with interstitial oedema in the lung. No macroscopic damages were observed in the pigs infected only with Pasteurella multocida. It can be concluded that the feed intake of FB1 in pigs may complicate or exacerbate the course of P. multocida serotype A infection.