Mycotoxins are secondary metabolites of fungi affecting human and animal health. Five classes of mycotoxins are of major concern in animal husbandry, namely aflatoxins, trichothecenes, zearalenone, ochratoxins, and fumonisins. Due to their diverse structure these fungal toxins are able to cause a great variety of acute symptoms in animals. Clay minerals have been used in animal nutrition to bind mycotoxins, but the binders are only very specific for aflatoxins but not for other toxins. A novel strategy to control the problem of mycotoxicoses in animals is the application of microorganisms capable of biotransforming mycotoxins into nontoxic metabolites. The microbes act in the intestinal tract of animals prior to the resorption of the mycotoxins. A Eubacterium (BBSH 797) strain is able to deactivate trichothecenes by reduction of the epoxide ring (CAST, Mycotoxins, Risks in Plant, Animal and Human Systems, Task Force Report 139, Council of Agricultural Science and Technology, Ames Iowa 2003, p. 10.; Binder, E. M., Binder, J., Ellend, N., Schaffer, E. et al., in: Miraglia, M., van Egmond, H., Brera, C., Gilbert, J. (Eds.), Mycotoxins and Phycotoxins--Developments in Chemistry, Toxicology and Food Safety, Alaken, Fort Collins 1996, pp. 279-285). This strain was isolated out of bovine rumen fluid and the mode of action was proven in vitro and also in vivo. Further a novel yeast strain, capable of degrading ochratoxin A and zearalenone was isolated and characterized (Bruinink, A., Rasonyi, T., Sidler, C., Nat. Toxins 1999, 6, 173-177; Schatzmayr, G., Heidler, D., Fuchs, E., Mohnl, M. et al., Mycotoxin Res. 2003, 19, 124-128.) Due to the yeasts affiliation to the genus of Trichosporon and its property to degrade mycotoxins this strain was named Trichosporon mycotoxinivorans (Trichosporon MTV, 115).

The mycotoxin fumonisin B1 (FB1) is a frequent contaminant of feed and causes various adverse health effects in domestic animals. Hence, effective strategies are needed to prevent the impact of fumonisins on livestock productivity. Here we evaluated the capability of the fumonisin carboxylesterase FumD to degrade FB1 to its less toxic metabolite hydrolyzed FB1 (HFB1) in the gastrointestinal tract of turkeys and pigs. First, an ex vivo pig model was used to examine the activity of FumD under digestive conditions. Within 2 h of incubation with FumD, FB1 was completely degraded to HFB1 in the duodenum and jejunum, respectively. To test the efficacy of the commercial application of FumD (FUMzyme) in vivo, female turkeys (n = 5) received either basal feed (CON), fumonisin-contaminated feed (15 mg/kg FB1+FB2; FB) or fumonisin-contaminated feed supplemented with FUMzyme (15 U/kg; FB+FUMzyme) for 14 days ad libitum. Addition of FUMzyme resulted in significantly decreased levels of FB1 in excreta, whereas HFB1 concentrations were significantly increased. Compared to the FB group (0.24 ± 0.02), the mean serum sphinganine-to-sphingosine (Sa/So) ratio was significantly reduced in the FB+FUMzyme group (0.19 ± 0.02), thus resembling values of the CON group (0.16 ± 0.02). Similarly, exposure of piglets (n = 10) to 2 mg/kg FB1+FB2 for 42 days caused significantly elevated serum Sa/So ratios (0.39 ± 0.15) compared to the CON group (0.14 ± 0.01). Supplementation with FUMzyme (60 U/kg) resulted in gastrointestinal degradation of FB1 and unaffected Sa/So ratios (0.16 ± 0.02). Thus, the carboxylesterase FumD represents an effective strategy to detoxify FB1 in the digestive tract of turkeys and pigs.

Concern about mycotoxins in aquaculture has been growing, partly due to the gradual replacement of animal-derived proteins, such as fish meal, by plant sources. Over a period of one year, 2,176 samples of different plant protein sources and 25 samples of finished aquaculture feeds were analysed. Samples were tested for aflatoxins (AF; sum of aflatoxin B1, B2, G1 and G2), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB; sum of fumonisin B1 and B2), T-2 toxin and ochratoxin A (full toxin screen). The following plant-based meals were analysed: soybean meal (SBM), wheat (WH), wheat bran (WB), maize (C), corn gluten meal (CGM), cottonseed meal (CSM), rapeseed/canola meal (R/CM) and rice bran (RB). The plant raw materials and aquaculture finished feeds were obtained from Asia and Europe. Finished feed samples from Asia were acquired from Vietnam, Indonesia and Myanmar, while from Europe they were sampled from Denmark, Austria, the Netherlands and Germany. Mycotoxins were found in most of the commodities and finished feeds analysed, showing that mycotoxins represent a risk for the development of the aquaculture sector. Generally, in Asian samples we observed that SBM, WH, WB, C, CGM, R/CM and RB were mostly contaminated with Fusarium mycotoxins (ZEA, DON and FB). CSM was contaminated primarily by AF and Fusarium toxins (ZEA and DON) at lower concentrations. European samples were contaminated mainly by Fusarium mycotoxins. The co-occurrence of mycotoxins in all commodities was high, raising the probability of co-occurrence in finished feeds. An accumulation of mycotoxins on the processed plant-based ingredients (e.g. CGM and WB) was observed when compared to the respective whole grains (C and WH, respectively). Compared to results obtained in 2014, finished feeds presented lower contamination levels, but the co-occurrence risk increased.

Little is known about the effects of commonly found levels of Fusarium mycotoxins on the performance, metabolism, and immunity of dairy cattle. We investigated the effects of regular contamination levels, meaning contamination levels that can be commonly detected in dairy feeds, of deoxynivalenol (DON) and fumonisins (FB) in total mixed ration (TMR) on the performance, diet digestibility, milk quality, and plasma liver enzymes in dairy cows. This trial examined 12 lactating Holstein dairy cows using a 3-period × 3-treatment Latin Square design. The experimental period was 21 d of mycotoxin exposure followed by 14 d of washout. During treatment periods, cows received one of 3 diets: (1) CTR (control) diet of TMR contaminated with 340.5 µg of DON/kg of dry matter (DM) and 127.9 µg FB/kg of DM; (2) MTX diet of TMR contaminated with Fusarium mycotoxins at levels higher than CTR but below US and European Union guidelines (i.e., 733.0 µg of DON/kg of DM and 994.4 µg of FB/kg of DM); or (3) MDP diet, which was MTX diet supplemented with a mycotoxin deactivator product (i.e., 897.3 µg of DON/kg of DM and 1,247.1 µg of FB/kg of DM; Mycofix, 35 g/animal per day). During washout, all animals were fed the same CTR diet. Body weight, body condition score, DM intake, dietary nutrient digestibility, milk production, milk composition and rennet coagulation properties, somatic cell count, blood serum chemistry, hematology, serum immunoglobulin concentrations, and expression of multiple genes in circulating leucocytes were measured. Milk production was significantly greater in the CTR group (37.73 kg/d) than in the MTX (36.39 kg/d) and the MDP (36.55 kg/d) groups. Curd firmness and curd firming time were negatively affected by the MTX diet compared with the other 2 diets. Furthermore, DM and neutral detergent fiber digestibility were lower after the MTX diet than after the CTR diet (67.3 vs. 71.0% and 42.8 vs. 52.3%). The MDP diet had the highest digestibility coefficients for DM (72.4%) and neutral detergent fiber (53.6%) compared with the other 2 diets. The activities of plasma liver transaminases were higher after the MTX diet than after the CTR and MDP diets. Compared with the CTR diet, the MTX diet led to slightly lower expression of genes related to immune and inflammatory functions, indicating that Fusarium mycotoxins had an immunosuppressive effect. Our results indicated that feed contaminated with regular levels of Fusarium mycotoxins adversely affected the performance, milk quality, diet digestibility, metabolic variables, and immunity of dairy cows, and that supplementation with mycotoxin deactivator product counteracted most of these negative effects.

Reduction of the Fusarium mycotoxin deoxynivalenol (DON) in animal feed by treatment with sodium bisulfite and sodium metabisulfite has been successfully demonstrated in several studies. All of them reported formation of one DON sulfonate of strongly reduced toxicity compared to DON. The starting point of the present work was investigation of different sulfur reagents for reduction of DON. In the course of these experiments, three different DON sulfonates termed DON sulfonate 1 (1), DON sulfonate 2 (2), and DON sulfonate 3 (3) were identified and structurally elucidated by UHPLC-HRMS/MS as well as NMR spectroscopy. Compound 1 is characterized by loss of the epoxide group, and 2 by formation of a hemiketal. Compound 3 is an equilibrating mixture of two isomers, a ketone and a hemiketal. The MS/MS pattern can be used to differentiate the three DON sulfonates, despite their same mass and molecular formula. Investigation of parameters influencing formation and stability of DON sulfonates revealed that rapid formation of 1 and 2 occurs at alkaline pH, whereas at acidic pH, slow formation of 3 takes place, irrespective of the sulfur reagent used. Whereas 1 and 2 are stable across a broad pH range, 3 decomposes to DON, 1, and 2 at alkaline pH. In addition, both 2 and 3 are unstable in solid form. The formation, characterization, and stability of three novel DON sulfonates with respect to results from previous studies are discussed, providing insights of relevance for detoxification of DON-containing animal feed.