Novel yeast isolated from broilers' feedstuff, gut and faeces as aflatoxin B1 adsorbents.

AIMS: To isolate and characterize native yeast strains from broilers' environment as feedstuff, faeces and gut, and to evaluate their binding capacity for aflatoxin B1 (AFB1 ). METHODS AND RESULTS: A total of nine yeast strains were isolated: three from feedstuff identified as Pichia kudriavzevii (2) and Clavispora lusitaniae (1), two from gut identified as Candida tropicalis and four from faeces identified as Cl. lusitaniae (3) and Cyberlindnera fabianii (1). AFB1 binding percentages varied among yeast strains and with AFB1 concentrations. To carry out adsorption studies, one strain from each genus and each origin was selected as follows: Cl. lusitaniae and P. kudriavzevii from feedstuff, Cl. lusitaniae and Cy. fabianii from faeces and Ca. tropicalis from gut. The most appropriate concentrations for cells and toxin were 107 cells per ml and 100 ng ml-1 of AFB1 respectively. All the tested yeast strains showed similar adsorption capacities independently of the origin. The adsorption isotherm studies in all yeasts assayed showed behaviour of L type or Langmuir and a varied affinity for the toxin. The stability of the AFB1 -yeast complex demonstrated the irreversibility of the binding process. CONCLUSION: Yeast strains tested in this study constitute potential AFB1 adsorbents and they possess the advantage to be native from the avian environment. SIGNIFICANCE AND IMPACT OF THE STUDY: This study makes a contribution to using native yeasts from broilers' environment for controlling chronic aflatoxicosis in avian production.

Phenolic acid protects of renal damage induced by ochratoxin A in a 28-days-oral treatment in rats.

The present study aimed to characterize the chlorogenic acid (ChlA) capacity to reverse the toxic effects induced by ochratoxin A (OTA) in a subacute toxicity test in rats. Male Wistar rats were fed orally by gavage for 28 days with OTA (0.4mg/kg bw/day), ChlA (5mg/kg bw/day) or the combination OTA (0.4mg/kg bw/day)+ChlA (5mg/kg bw/day). No deaths, no decrease in feed intake or body weight in any experimental group were recorded. The negative control group and the animals treated with ChlA alone showed no changes in any parameters evaluated. In OTA-treated group significant changes such as decrease in urine volume, proteinuria, occult blood, increase in serum creatinine values; decrease in absolute and relative kidney weight and characteristics histopathological lesions that indicated kidney damage were observed. However, limited effect on oxidative stress parameters were detected in kidneys of OTA-treated group. Animals treated with the combination OTA+ChlA were showed as negative control group in the evaluation of several parameters of toxicity. In conclusion, ChlA, at given concentration, improved biochemical parameters altered in urine and serum and pathological damages in kidneys induced by OTA exposure, showing a good protective activity, but not by an apparent antioxidant mechanism.

Ecophysiology of environmental Aspergillus fumigatus and comparison with clinical strains on gliotoxin production and elastase activity.

UNLABELLED: The aim of this manuscript was to study the influence of water activity (aW ) and pH in the ecophysiological behaviour of Aspergillus fumigatus strains at human body temperature. In addition, gliotoxin production and enzymatic ability among environmental (n = 2) and clinical (n = 5) strains were compared. Ecophysiological study of environmental strains was performed on agar silage incubated at 37°C, studying the interaction at eight aW levels (0·8, 0·85, 0·9, 0·92, 0·94, 0·96, 0·98 and 0·99) and eight pH levels (3·5, 4, 4·5, 5, 6, 7, 7·5 and 8). Considering the influence of the assumed lung conditions on growth of A. fumigatus (aW 0·98/0·99 and pH of 7/7·5), the optimal condition for the development of A. fumigatus RC031 was at aW 0·99 at pH 7. At aW 0·98/0·99 and pH of 7/7·5, the highest growth rate and the lowest lag phase was reported, whereas there were no significant differences at aW 0·98/0·99 and pH 7/7·5 interactions on growth of A. fumigatus RC032. Gliotoxin production of A. fumigatus strains was evaluated. The gliotoxin production was similar in clinical and environmental strains. Elastin activity was studied in solid medium, highest elastase activity index was found for clinical strain A. fumigatus RC0676, followed by the environmental strain A. fumigatus RC031. Opportunistic environmental strains can be considered as pathogenic in some cases when rural workers are exposed constantly to handling silage. SIGNIFICANCE AND IMPACT OF THE STUDY: Aspergillus fumigatus is one of the main opportunist pathogen agents causing invasive aspergillosis. Rural workers present a constant exposition to A. fumigatus spores caused by feed-borne manipulation. In this study, environmental A. fumigatus strains were able to grow and produce gliotoxin onto the studied conditions including the lung ones. Environmental and clinical strains were physiologically similar and could be an important putative infection source in rural workers.

Gliotoxin production by Aspergillus fumigatus strains from animal environment. Micro-analytical sample treatment combined with a LC-MS/MS method for gliotoxin determination.

In this study, gliotoxin production by Aspergillus fumigatus strains from animal environment is studied. Moreover, a rapid, easy and environment-friendly micro-analytical sample treatment procedure coupled with LC-MS/MS was applied for the determination of gliotoxin from A. fumigatus cultures. The ability of gliotoxin production by 143 strains was assayed in yeast extract sucrose agar, and 1 ml of chloroform was used for toxin extraction without further clean-up. Mean recoveries at two spiking levels (2500 and 7000 ng/g; n = 6) were 100.3 ± 6.6 % relative SD (RSD) and 92.4 ± 3.8 % RSD. Repeatability and within-laboratory reproducibility for different concentration levels of gliotoxin (25 to 1000 ng/ml; n = 12) ranged from 0.3 to 5.4 % RSD and from 3.9 to 12.7 % RSD, respectively. The detection limit of the analytical method was 3.5 ng/g. The ability for gliotoxin production by A. fumigatus revealed that 61.5 % of the strains were able to produce the toxin at levels ranging from LOQ to 3430.5 ng/g. However, all the tested samples had similar percentages of producing strains (81.8 to 86.6 %). The micro-analytical sample treatment coupled with LC-MS/MS detection is a precise and useful methodology for determining gliotoxin from fungal extracts of A. fumigatus and allows working both fast and safely and also reducing the effect on the environment. This toxin plays a critical role in the pathobiology of A. fumigatus, and its presence in animal environments could affect animal health and productivity; in addition, there are risks of contamination for rural workers during handling and storage of animal feedstuffs.

Polyphenols as possible bioprotectors against cytotoxicity and DNA damage induced by ochratoxin A.

The present study aimed to investigate the protective effects of luteolin (L), chlorogenic acid (ChlA) and caffeic acid (CafA) against cyto-genotoxic effects caused by OTA. Vero cells and rat lymphocytes were used and viability was measured by neutral red uptake, MTT and trypan blue dye exclusion method. L (50 and 100µg/mL), ChlA (100 and 200µg/mL) and CafA (10-50µg/mL) reduced the damage induced by OTA (10µg/mL) on both cells type shown a good protective effect. The comet and micronucleus tests in Balb/c mice were performed. ChlA (10mg/kg bw) reduced OTA (0.85mg/kg bw)-induced DNA damage on blood and bone marrow cells, CafA (10mg/kg bw) showed protective effect only in blood cells and luteolin (2.5mg/kg bw) failed to protect DNA integrity on cells. In conclusion, polyphenols tested reduced the toxicity caused by OTA on different target cells with good protective effect, being ChlA the compound that showed the best effects.

Physiological behaviour of gliotoxigenic Aspergillus fumigatus sensu stricto isolated from maize silage under simulated environmental conditions.

Environmental conditions play a key role in fungal development. During the silage production process, humidity, oxygen availability and pH vary among lactic-fermentation phases and among different silage sections. The aim of this work was to study the physiological behaviour of gliotoxicogenic Aspergillus fumigatus strains isolated from maize silage under simulated natural physicochemical conditions - different water activities (a(W)), temperatures (Tº), pH and oxygen pressure - on the growth parameters (growth rate and lag phase) and gliotoxin production. The silage was made with the harvested whole maize plant that was chopped and used for trench-type silo fabrication. Water activity and pH of the silage samples were determined. Total fungal counts were performed on Dichloran Rose Bengal Chloramphenicol agar and Dichloran 18% Glycerol agar. The morphological identification of A. fumigatus was performed with different culture media and at different growth temperature to observe microscopic and macroscopic characteristics. Gliotoxin production by A. fumigatus was determined by HPLC. All strains isolated were morphologically identified as A. fumigatus. Two A. fumigatus strains isolated from the silage samples were selected for the ecophysiological study (A. fumigatus sensu stricto RC031 and RC032). The results of this investigation showed that the fungus grows in the simulated natural physicochemical conditions of corn silage and produces gliotoxin. The study of the physiological behaviour of gliotoxigenic A. fumigatus under simulated environmental conditions allowed its behaviour to be predicted in silage and this will in future enable appropriate control strategies to be developed to prevent the spread of this fungus and toxin production that leads to impairment and reduced quality of silage.

In vitro aflatoxin B1 binding capacity by two Enterococcus faecium strains isolated from healthy dog faeces.

AIM: This study evaluated the binding capacity of aflatoxin B1 (AFB1 ) by two Enterococcus faecium strains (MF4 and GJ40) isolated from faeces from healthy dogs. MATERIALS AND METHODS: The binding assay was performed using 50 and 100 ppb of AFB1 analysing the effects of the viability, incubation time and pH on AFB1 binding. Binding stability was determined by washing three times the bacteria-AFB1 complexes with phosphate buffer saline. RESULTS: Both GJ40 and MF4 strains have the ability to remove AFB1 from aqueous solution. Viable cells were slightly more effective in AFB1 binding than nonviable ones for both strains. Enterococcus faeciumGJ40 removes 24-27% and 17-24%, and Ent. faeciumMF4 removes 36-42% and 27-32% of AFB1 (50 and 100 ppb, respectively) throughout a 48 h incubation period. In general, the removal of AFB1 was highest at pH 7.00 for both strains. The stability of the bacteria-AFB1 complex formed was found to be high (up to 50% of AFB1 remained bounded in bacterial cell after three washes with phosphate buffered saline). CONCLUSION: The Ent. faecium strains assayed are capable of removing AFB1 under different conditions in vitro. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first AFB1 binding assay performed with Ent. faecium strains isolated from dog faeces, being an interesting strategy for AFB1 decontamination of pet food.

Negligible effects of tryptophan on the aflatoxin adsorption of sodium bentonite.

The main objective of this study was to determine if the competitive adsorption of tryptophan (Trp) and aflatoxin B1 (AFB1) could potentially affect the ability of a sodium bentonite (NaB) to prevent aflatoxicosis in monogastric animals. The adsorption of Trp and AFB1 on this adsorbent is fast and could be operating on the same time-scale making competition feasible. In vitro competitive adsorption experiments under simulated gastrointestinal conditions were performed. A high affinity of the clay for Trp and NaB was observed. The effect of an excess of KCl to mimic the ionic strength of the physiological conditions were also investigated. A six-times decrease in the Trp surface excess at saturation was observed. A similar behaviour was previously found for AFB1 adsorption. Taking into account the amount of Trp adsorbed by the clay and the usual adsorbent supplementation level in diets, a decrease in Trp bioavailability is not expected to occur. Tryptophan adsorption isotherms on NaB were 'S'-shaped and were adjusted by the Frumkin-Fowler-Guggenheim model. The reversibility of the adsorption processes was investigated in order to check a potential decrease in the ability of NaB to protect birds against chronic aflatoxicoses. Adsorption processes were completely reversible for Trp, while almost irreversible for AFB1. In spite of the high affinity of the NaB for Trp, probably due to the reversible character of Trp adsorption, no changes in the AFB1 adsorption isotherm were observed when an excess of the amino acid was added to the adsorption medium. As a consequence of the preferential and irreversible AFB1 adsorption and the reversible weak binding of Trp to the NaB, no changes in the aflatoxin sorption ability of the clay are expected to occur in the gastrointestinal tract of birds.

Genotoxicity and cytotoxicity evaluation of probiotic Saccharomyces cerevisiae RC016: a 60-day subchronic oral toxicity study in rats.

AIMS: To acquire data on the safety-in-use of the probiotic Saccharomyces cerevisiae RC016 and test its ability to reduce genotoxicity caused by dietary aflatoxins (AFs). METHODS AND RESULTS: The probiotic was orally administered to Wistar rats. Six groups (n = 6) were arranged: feed and probiotic controls, two levels of AFs-contaminated feed and two treatments including both the probiotic and the toxin. Genotoxiciy and cytotoxicity were evaluated with the bone marrow micronuclei assay and the comet assay and internal organs were macroscopically and microscopically examined. The tested S. cerevisiae strain did not cause genotoxicity or cytotoxicity in vivo, and it was able to attenuate AFs-caused genotoxicity. Saccharomyces cerevisiae RC016 did not cause any impairment on the rats' health and it showed no negative impact on the weight gain. Moreover, RC016 improved zootechnical parameters in AFs-treated animals. The beneficial effects were likely to be caused by adsorption of AFs to the yeast cell wall in the intestine and the consequent reduction in the toxin's bioavailability. CONCLUSIONS: The dietary administration of RC016 does not induce genotoxicity or cytotoxicity to rats. SIGNIFICANCE AND IMPACT OF THE STUDY: Incorporation of RC016 in the formulation of feed additives increases animal productivity. Similar effects may even occur in human food applications.

Typing clinical and animal environment Aspergillus fumigatus gliotoxin producer strains isolated from Brazil by PCR-RFLP markers.

UNLABELLED: Aspergillus fumigatus, a well-known human and animal pathogen causing aspergillosis, has been historically identified by morphological and microscopic features. However, recent studies have shown that species identification on the basis of morphology alone is problematic. The aim of this work was to confirm the taxonomic state at specie level of a set of clinical (human and animal) and animal environment A. fumigatus strains identified by morphological criteria applying a PCR-RFLP assay by an in silico and in situ analysis with three restriction enzymes. The A. fumigatus gliotoxin-producing ability was also determined. Previous to the in situ PCR-RFLP analysis, an in silico assay with BccI, MspI and Sau3AI restriction enzymes was carried out. After that, these enzymes were used for in situ assay. All A. fumigatus strains isolated from corn silage, human aspergillosis and bovine mastitis and high per cent of the strains isolated from cereals, animal feedstuff and sorghum silage were able to produce high gliotoxin levels. Also, all these strains identified by morphological criteria as A. fumigatus, regardless of its isolation source, had band patterns according to A. fumigatus sensu stricto by PCR-RFLP markers. SIGNIFICANCE AND IMPACT OF THE STUDY: Aspergillus fumigatus is a well-known human and animal pathogen causing aspergillosis. In this study, clinical (human and animal) and animal environment strains were able to produce high gliotoxin levels and had band profiles according to A. fumigatus sensu stricto by PCR-RFLP markers. The results obtained here suggest that strains involved in human and animal aspergillosis could come from the animal environment in which A. fumigatus is frequently found. Its presence in animal environments could affect animal health and productivity; in addition, there are risks of contamination for rural workers during handling and storage of animal feedstuffs.

Evaluation of Saccharomyces cerevisiae as an antiaflatoxicogenic agent in broiler feedstuffs.

Aflatoxins (AF) are the most important mycotoxins produced by toxigenic strains of various Aspergillus spp. Biological decontamination of mycotoxins using microorganisms is a well-known strategy for the management of mycotoxins in feeds. Saccharomyces cerevisiae strains have been reported to bind aflatoxin B1 (AFB1). The aim of this study was to evaluate the ability of S. cerevisiae CECT 1891 in counteracting the deleterious effects of AFB1 in broiler chicks. Experimental aflatoxicosis was induced in 6-d-old broilers by feeding them 1.2 mg of AFB1/kg of feed for 3 wk, and the yeast strain was administrated in feed (10(10) cells/kg), in the drinking water (5 × 10(9) cells/L), or a combination of both treatments. A total of 160 chicks were randomly divided into 8 treatments (4 repetitions per treatment). Growth performance was measured weekly from d 7 to 28, and serum biochemical parameters, weights, and histopathological examination of livers were determined at d 28. The AFB1 significantly decreased the BW gain, feed intake, and impaired feed conversion rate. Moreover, AFB1 treatment decreased serum protein concentration and increased liver damage. The addition of S. cerevisiae strain to drinking water, to diets contaminated with AFB1, showed a positive protection effect on the relative weight of the liver, histopathology, and biochemical parameters. Furthermore, dietary addition of the yeast strain to drinking water alleviated the negative effects of AFB1 on growth performance parameters. In conclusion, this study suggests that in feed contaminated with AFB1, the use of S. cerevisiae is an alternative method to reduce the adverse effects of aflatoxicosis. Thus, apart from its excellent nutritional value, yeast can also be used as a mycotoxin adsorbent.

Effect of monogastric and ruminant gastrointestinal conditions on in vitro aflatoxin B1 adsorption ability by a montmorillonite.

The main objective of this study was to evaluate the interference of environment components on the in vitro evaluation of aflatoxin B1 adsorption capacity of sodium bentonite under simulated gastrointestinal conditions of monogastric and ruminant animals. Sodium bentonite showed a high aflatoxin B1 affinity with all of the assays. Langmuir or sigmoid isotherms were found in different assays. Both the affinities and the surface excesses at monolayer saturation were affected by the buffer components. The specific influence of ions in each buffer solution was investigated. A significant decrease in the surface excess at monolayer saturation was observed under ionic strength control. A change in the isotherm shape from sigmoidal to Langmuir was observed with the increase in the sodium chloride concentration. This was attributed to the decrease in the importance of lateral interaction between adsorbed toxin molecules compared with surface-molecules interactions under a high salt coverage. The presence of rumen fluid components in the adsorption environment decreased the aflatoxin B1 maximum adsorption capacity of sodium bentonite. Despite the high affinity of this adsorbent to capture aflatoxin B1, different substances present in the environment could affect the adsorption capacity, at least at low toxin concentrations that mimic chronic exposure. The environment of the gastrointestinal tract, in either monogastric or ruminant animals, affect in vivo aflatoxin B1 adsorption by sodium bentonite and should be taken into account when an in vitro performance evaluation is done.

Fungi and mycotoxins in silage: an overview.

The present revision shows the early and current knowledge in the field of silage fungi and mycotoxins explaining the relevance of fungi and mycotoxins in silage. The problem does not end in animal disease or production losses as mycotoxins in feed can lead to the presence of their metabolic products in dairy products, which will be eventually affecting human health, mainly infants. Silage is green forage preserved by lactic fermentation under anaerobic conditions. This ecosystem maintains its quality and nutritional value depending on interactions among physical, chemical and biological agents. Forages used for ensilage are naturally in contact with yeasts and filamentous fungi, and the contamination often occurs in the field and can also occur during harvesting, transport, storage. Moreover, postharvest poor management can lead to a rapid spoilage. Studies on fungal contamination of dairy cattle feed have shown how corn silage influences the contamination degree of feed supplied to livestock. Increasing knowledge in this area will help elucidate the influence that this microbiota exerts on production and/or degradation of mycotoxins present in silage. Some of these fungi, although opportunist pathogens, are relevant epidemiologically and represent a high risk of contamination to farm workers who handle them improperly.

Selection of lactic acid bacteria to promote an efficient silage fermentation capable of inhibiting the activity of Aspergillus parasiticus and Fusarium gramineraum and mycotoxin production.

AIMS: To select lactic acid bacteria with potential silage inoculant properties. The bio-control activity against mycotoxicogenic fungi and the presence of antibiotics resistance gene were also evaluated. METHODS AND RESULTS: Lactobacillus rhamnosus RC007 and Lactobacillus plantarum RC009 were selected on the basis of growth rate and efficacy in reducing the pH of maize extract medium; therefore, they were evaluated for their bio-control ability against Fusarium graminearum and Aspergillus parasiticus. Studies on lag phase, growth rate and aflatoxin B1 (AFB1) and zearalenone (ZEA) production were carried out in vitro under different regimes of aw (0·95 and 0·99); pH (4 and 6); temperature (25 and 37°C); and oxygen availability (normal and reduced). Lactobacillus rhamnosus RC007 was able to completely inhibit the F. graminearum growth at all assayed conditions, while Lact. plantarum RC009 only did it at pH 4. Both Lactobacillus strains were able to significantly reduce the A. parasiticus growth rate mainly at 0·99 aw . A decrease in ZEA production was observed as result of Lactobacillus strains -F. graminearum interaction; however, the A. parasiticus- Lact. plantarum interaction resulted in an increased AFB1 production. Lactobacillus rhamnosus RC007 proved to have no genes for resistance to the tested antibiotics. CONCLUSIONS: The ability of Lact. rhamnosus RC007 to rapidly drop the pH and to inhibit fungal growth and mycotoxin production and the absence of antibiotic resistance genes shows the potential of its application as inoculant and bio-control agent in animal feed. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated the importance of selecting bacteria for silage inoculants not only for the improvement of silage fermentation but also for their effects on mycotoxicogenic fungi and the resulting mycotoxin production due to the risk that they may involve.

In vitro study on the effect of Saccharomyces cerevisiae strains on growth and mycotoxin production by Aspergillus carbonarius and Fusarium graminearum.

The effect of Saccharomyces cerevisiae RC008 and RC016 strains, previously selected based on their aflatoxin B1 mycotoxin binding ability and beneficial properties, against Aspergillus carbonarius and Fusarium graminearum under different interacting environmental conditions was evaluated. In vitro studies on the lag phase, growth rate and ochratoxin A/zearalenone and DON production were carried out under different regimens of a(w) (0.95 and 0.99); pH (4 and 6); temperature (25 and 37 °C) and oxygen availability (normal and reduced). Both yeast strains showed antagonistic activity and decreasing growth rate compared to the control. In general, the RC016 strain showed the greatest inhibitory activity. Except at the interacting condition 0.95 a(W), normal oxygen availability and 37 °C, at both pH values, A. carbonarius and F. graminearum were able to produce large amounts of mycotoxins in vitro. In general, a significant decrease in levels of mycotoxins in comparison with the control was observed. S. cerevisiae RC008 and RC016 could be considered as effective agents to reduce growth and OTA, ZEA and DON production at different interacting environmental conditions, related to those found in stored feedstuff. The beneficial and biocontrol properties of these strains are important in their use as novel additives for the control of mycotoxigenic fungi in stored feedstuffs.

Statistical optimization of culture conditions for biomass production of probiotic gut-borne Saccharomyces cerevisiae strain able to reduce fumonisin B1.

AIM: To evaluate the ability of probiotic Saccharomyces cerevisiae RC016 strain to reduce fumonisin B(1) (FB(1)) in vitro and to optimize the culture conditions for the growth of the yeast employing surface response methodology. METHODS AND RESULTS: Using Plackett-Burman screening designs (PBSD) and central composite designs (CCD), an optimized culture medium containing (g l(-1)) fermentable sugars provided by sugar cane molasses (CMs), yeast extract (YE) and (NH(4))(2) HPO(4) (DAP) was formulated. The S. cerevisiae RC016 strain showed the greatest binding at all assayed FB1 concentration. The CMs, YE, DAP concentrations and incubation time influenced significantly the biomass of S. cerevisiae RC016. CONCLUSION: A combination of CMs 17%; YE 4·61 g l(-1) and incubation time 60 h was optimum for maximum biomass of S. cerevisiae RC016. SIGNIFICANCE AND IMPACT OF THE STUDY: The importance of this work lies in the search for live strains with both probiotic and fumonisin B1 decontamination properties that could be sustainably produced in a medium just containing cheap carbon, nitrogen and phosphorus sources and would be included in a novel product to animal feed.

Survey of Aspergillus section Flavi and aflatoxin B(1) in brewer's grain used as pig feedstuff in Córdoba, Argentina.

Brewing industry by-products are important animal feedstuff alternatives for local swine producers in Córdoba, Argentina. The high content of nutrients makes these by-products vulnerable to bacterial and fungal contamination. The objectives of the present study were (1) to determine the presence of Aspergillus section Flavi in brewer's grain used to feed pigs and (2) to evaluate the incidence of aflatoxin B(1) in the substrate. Total fungal count of most samples exceeded the levels proposed as feed quality limits, and most Aspergillus section Flavi strains found were able to produce high amounts of AFB(1) in vitro. However, the incidence of AFB(1) was low. The presence of contamination by aflatoxicogenic species in feedstuff might affect the productivity of swine producers and indirectly represents a public health issue.

The corn influence on the adsorption levels of aflatoxin B1 and zearalenone by yeast cell wall.

AIMS: To in vitro evaluate the influence of the corn on the adsorption levels of aflatoxin B1 (AFB1) and zearalenone (ZEA) by yeast cell walls (YCWs). METHODS AND RESULTS: Two commercial YCWs were studied. The YCWs contain different percentages of polysaccharides. YCW1 and 2 contain 5.9 and 21% of mannans and 17.4 and 23% of ß-glucans, respectively. Each YCW was resuspended in pH 2 and pH 6 buffer solutions. Corn was used to study the matrix influence. An aliquot of 500 µl YCW suspension was added to each microtube containing 500 µl of 0.1, 0.25, 0.5, 1, 2.5 and 5 µg ml(-1) AFB(1) or 0.5, 5, 10, 20 and 50 µg ml(-1) ZEA. Microtubes were kept with mechanical agitation at 37 °C for 30 min and then centrifuged for 10 min at 16,873 g and; the supernatants were quantified by high-pressure liquid chromatography. The amount of bound toxin was plotted as a function of the amount of added toxin according to mathematical expressions proposed by three theoretical models. Both YCWs were capable of adsorbing AFB(1) and ZEA in amounts from 0.061 to 0.40 and from 0.10 and 0.26 g g(-1), respectively. In the presence of the matrix, both adsorbents were not able to adsorb AFB(1) . However, they could adsorb ZEA at levels from 0.03 to 0.23 g g(-1). CONCLUSIONS: Both YCWs adsorbed ZEA in the presence of corn and also under simulated gastrointestinal pH conditions. These results suggest that the studied YCWs are potential candidates for ZEA adsorption. SIGNIFICANCE AND IMPACT OF THE STUDY: Several in vitro assays have informed the ability of different substrates including yeast walls to adsorb AFB(1) and ZEA; none of them have evaluated their ability to adsorb AFB(1) and ZEA in the presence of the corn. The corn matrix can influence the adsorption phenomena of these mycotoxins.