Zearalenone (ZEN)-degrading enzymes are a promising strategy to counteract the negative effects of this mycotoxin in livestock. The reaction products of such enzymes need to be thoroughly characterized before technological application as a feed additive can be envisaged. Here, we evaluated the estrogenic activity of the metabolites hydrolyzed zearalenone (HZEN) and decarboxylated hydrolyzed zearalenone (DHZEN) formed by hydrolysis of ZEN by the zearalenone-lactonase Zhd101p. ZEN, HZEN, and DHZEN were tested in two in vitro models, the MCF-7 cell proliferation assay (0.01–500 nM) and an estrogen-sensitive yeast bioassay (1–10,000 nM). In addition, we compared the impact of dietary ZEN (4.58 mg/kg) and equimolar dietary concentrations of HZEN and DHZEN on reproductive tract morphology as well as uterine mRNA and microRNA expression in female piglets (n = 6, four weeks exposure). While ZEN increased cell proliferation and reporter gene transcription, neither HZEN nor DHZEN elicited an estrogenic response, suggesting that these metabolites are at least 50–10,000 times less estrogenic than ZEN in vitro. In piglets, HZEN and DHZEN did not increase vulva size or uterus weight. Moreover, RNA transcripts altered upon ZEN treatment (EBAG9, miR-135a-5p, miR-187-3p and miR-204-5p) were unaffected by HZEN and DHZEN. Our study shows that both metabolites exhibit markedly reduced estrogenicity in vitro and in vivo, and thus provides an important basis for further evaluation of ZEN-degrading enzymes.

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The contamination of animal feed with mycotoxins represents a worldwide problem for the animal industry. The most applied method for protecting animals against aflatoxicosis is the utilization of clay minerals. In the course of a research project adsorption experiments were performed in buffer solutions in order to evaluate the ability to bind Aflatoxin B1 (AfB1) at various pH-values. In order to investigate the strength of binding, the chemisorption index was calculated. Isothermal analysis was used to determine the values for the maximum adsorption capacity. Adsorption experiments in simulated gastrointestinal fluid and real gastric juice were carried out. Furthermore binding capability of the materials regarding selected vitamins was examined. Special attention was paid to the formation of AfB2a during experimental conditions. Based on the obtainedin vitro results, highly promising sorbent materials were ranked for furtherin vivo studies. Some adsorbing bentonites were also analysed mineralogically, but the results did not indicate which smectite property influences the adsorption process for AfB1.

BACKGROUNDLactic acid is an important biorefinery platform chemical. The use of thermophilic amylolytic microorganisms to produce lactic acid by fermentation constitutes an efficient strategy to reduce operating costs, including raw materials and sterilization costs.RESULTSA process for the thermophilic production of lactic acid by Geobacillus stearothermophilus directly from potato starch was characterized and optimized. Geobacillus stearothermophilus DSM 494 was selected out of 12 strains screened for amylolytic activity and the ability to form lactic acid as the major product of the anaerobic metabolism. In total more than 30 batches at 3–l scale were run at 60 °C under non-sterile conditions. The process developed produced 37 g L−1 optically pure (98%) L-lactic acid in 20 h from 50 g L−1 raw potato starch. As co-metabolites smaller amounts (<7% w/v) of acetate, formate and ethanol were formed. Yields of lactic acid increased from 66% to 81% when potato residues from food processing were used as a starchy substrate in place of raw potato starch.CONCLUSIONSPotato starch and residues were successfully converted to lactic acid by G. stearothermophilus. The process described in this study provides major benefits in industrial applications and for the valorization of starch-rich waste streams. © 2015 The Authors.Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Aflatoxins are a class of mycotoxins that impair poultry health and performance. Some clays have the ability to adsorb aflatoxins. In our study, mineralogical composition of the tested clays was confirmed by powder X-ray diffraction and simultaneous thermal analysis and their properties like pH, electrical conductivity, exchangeable cations, cation exchange capacity and clay content were determined. For their in vitro assessment regarding aflatoxin B1 (AFB1) adsorption, adsorption tests under ‘intensified conditions’ (low adsorbent and high toxin concentration) were carried out in buffers at various pH values and in real gastric juice followed by isothermal analysis in phosphate buffer. In vivo we used a completely randomised design with 4 replicate pens of 5 chicks assigned to each dietary treatment from hatch to 21 days. Dietary treatments included a negative and a positive control diet (2 mg/kg AFB1), and treatment groups receiving 2 mg/kg AFB1 and 0.5% of one of 8 adsorbents. Results of in vitro experiments ranked the adsorbents as ‘good’ (R, MB, B7, M32, M34, M5; 6 bentonites containing a cis-vacant smectite), ‘average’ (bentonite C2 containing a trans-vacant smectite) or ‘poor’ (zeolite Z08, containing clinoptilolite). The addition of AFB1 significantly reduced feed intake and/or body weight gain of the chicks compared to the negative control and to the treatment groups, except for C2 and Z08. Except Z08, all adsorbents numerically decreased the liver weight compared to the AFB1-fed group. Kidney weights were significantly increased by the addition of AFB1 compared to the control and most adsorbents, except C2 and Z08. Similarly, ‘good’ adsorbents significantly prevented the decrease in serum albumin and serum total protein. The ability of adsorbents to ameliorate AFB1 toxicity in poultry basically correlated with the in vitro findings meaning that ‘poor’ and ‘average’ adsorbents did not (Z08) or only partially (C2) protect against AFB1 in vivo.