Using bentonites to adsorb aflatoxin is an effective method of minimizing the toxicity of aflatoxin to animals and humans. Early studies indicated a more than 10-fold difference in aflatoxin adsorption capacity among different bentonites. The determining mineralogical and chemical properties of the clays in aflatoxin adsorption are still poorly understood. The objective of this study was to test the hypothesis that a bentonite’s selectivity and adsorption capacity for aflatoxin is mainly determined by the ‘size matching’ requirement, on a nm scale, between the non-polar interlayer surface domains and the aflatoxin molecules. The non-polar surface domain size of smectites was varied by (1) selecting smectites with different charge densities; and (2) changing the valence and the size of exchange cations to control the amount of water in the hydration shells of the cations. Infrared spectroscopy and X-ray diffraction were also used to characterize the aflatoxin-smectite complexes to investigate if layer-charge density would affect the bonding strength between aflatoxin and the minerals. A large aflatoxin adsorption capacity and high selectivity for aflatoxin were achieved by selecting smectites that had low charge density as represented by their <110 meq/100 g cation exchange capacity. An individual smectite’s selectivity and adsorption capacity for aflatoxin could be enhanced or weakened by replacing the exchange cation. When the smectite was saturated with divalent cations that have smaller hydrated radius (e.g. Ba2+), the smectite’s adsorption capacity and affinity for aflatoxin were enhanced. Aflatoxin entered the interlayer of all six smectites tested. The strength of its bonding to the smectites was not affected by the layer-charge density of the smectites. The results confirmed the importance of nm-scale polarity and size match between aflatoxin molecules and the adsorbing sites on smectite. The high selectivity for aflatoxin can be achieved by selecting a smectite with adequate charge density or by replacing the exchange cations with divalent cations that have low hydration energy.

Numerous experiments have verified that smectites can adsorb aflatoxin B1 (AfB1) effectively and the efficiency of this process depends heavily on the chemical, physical, and mineralogical characteristics of the smectite. Several relationships between these characteristics and AfB1 sorption have been determined experimentally, but the molecular mechanisms underlying these were not investigated. In the current study the effects of charge density, type of exchange cation, and charge origin (octahedral vs. tetrahedral) on AfB1 sorption on smectites were analyzed by a series of molecular simulations. The calculations confirmed the formation of water bridges between carbonyl groups of AfB1 molecules and interlayer cations. Flat orientation of AfB1 molecules on smectite surfaces was also confirmed. For larger amounts of AfB1 molecules in the intercalates, self-association of two AfB1 molecules bound by π–π interaction was shown. The thermodynamics of AfB1 sorption depends heavily on the water content in the structure, being optimal for basal distances corresponding to two layers of water. A clear preference for sorption of AfB1 on smectites with bivalent cations (Ba2+, Ca2+) and an octahedral origin of its layer charge was confirmed and this was explained as steric hindrance between hydrated ions and AfB1 molecules, which tend to lie flat on smectite surfaces devoid of ions. Ba-montmorillonite with a charge of 0.4 per half unit cell was shown to have the smallest and thus the best potential energy of adsorption compared to the other layer charges.

Chitosan (CTS) modified montmorillonite (Mnt) composites (CTS-Mnt), which have been widely reported for the adsorption of heavy-metal ions and biological dyes, have not been applied to the field of mycotoxin adsorption. The current study was focused on the preparation of CTS-Mnt by calcination as a mycotoxin adsorbent for the efficient removal of aflatoxin B1 (AFB1). The CTS-Mnt samples obtained were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and nitrogen adsorption/desorption analysis. The CTS-Mnt samples prepared at various calcination temperatures exhibited varying structural configurations, surface hydrophobicities, and texture properties. The results revealed that stable CTS-Mnt speciments, obtained at <350°C, displayed superior adsorption capacity for AFB1 from a simulated gastrointestinal tract, increasing from 0.51 mg/g of raw Mnt to 4.97 mg/g. With increased calcination temperature, the effect of pH on the adsorption process of AFB1 becomes negligible. This study demonstrates that the novel CTS-Mnt has tremendous potential as an AFB1 adsorbent.

The purposes of this study were to investigate the systemic and characteristic metabolites in the serum of dairy goats induced by aflatoxin B1 (AFB1) exposure and to further understand the endogenous metabolic alterations induced by it. A nuclear magnetic resonance (NMR)-based metabonomic approach was used to analyse the metabolic alterations in dairy goats that were induced by low doses of AFB1 (50 µg/kg DM). We found that AFB1 exposure caused significant elevations of glucose, citrate, acetate, acetoacetate, betaine, and glycine yet caused reductions of lactate, ketone bodies (acetate, β-hydroxybutyrate), amino acids (citrulline, leucine/isoleucine, valine, creatine) and cell membrane structures (choline, lipoprotein, N-acetyl glycoproteins) in the serum. These data indicated that AFB1 caused endogenous metabolic changes in various metabolic pathways, including cell membrane-associated metabolism, the tricarboxylic acid cycle, glycolysis, lipids, and amino acid metabolism. These findings provide both a comprehensive insight into the metabolic aspects of AFB1-induced adverse effects on dairy goats and a method for monitoring dairy animals exposed to low doses of AFB1.

Human exposure to aflatoxin is through the diet, and probiotics are able to bind aflatoxin and prevent its absorption in the small intestine. This study aimed to determine the effectiveness of a fermented milk drink containing Lactobacillus casei Shirota (LcS) (probiotic drink) to prevent aflatoxin absorption and reduce serum aflatoxin B1-lysine adduct (AFB1-lys) and urinary aflatoxin M1 concentrations. The present study was a randomised, double-blind, cross-over, placebo-controlled study with two 4-week intervention phases. In all, seventy-one subjects recruited from the screening stage were divided into two groups – the Yellow group and the Blue group. In the 1st phase, one group received probiotic drinks twice a day and the other group received placebo drinks. Blood and urine samples were collected at baseline, 2nd and 4th week of the intervention. After a 2-week wash-out period, the treatments were switched between the groups, and blood and urine samples were collected at the 6th, 8th and 10th week (2nd phase) of the intervention. No significant differences in aflatoxin biomarker concentrations were observed during the intervention. A within-group analysis was further carried out. Aflatoxin biomarker concentrations were not significantly different in the Yellow group. Nevertheless, ANOVA for repeated measurements indicated that AFB1-lys concentrations were significantly different (P=0·035) with the probiotic intervention in the Blue group. The 2nd week AFB1-lys concentrations (5·14 (sd 2·15) pg/mg albumin (ALB)) were significantly reduced (P=0·048) compared with the baseline (6·24 (sd 3·42) pg/mg ALB). Besides, the 4th week AFB1-lys concentrations were significantly lower (P<0·05) with probiotic supplementation than with the placebo. Based on these findings, a longer intervention study is warranted to investigate the effects of continuous LcS consumption to prevent dietary aflatoxin exposure.

A dairy cow model was established to measure the transmission of aflatoxin M1 (AFM1) into milk. Four Ayrshire mid-lactation dairy cows (ranging 590 – 650 kg body weight and averaging 4.5 years of age) were used in a crossover experimental design in which each cow acted as its own control and was subjected to four dietary treatments administered as six 12-day feeding periods followed by a 7-day washout period. Periods I – VI comprised a 7 d of adaptation followed by 5 d of sampling. Period VII was a 7-d washout with sampling in the final two days. From each morning's milking, yield was recorded and sampled for AFM1 analysis by HPLC. Treatments included a negative control, contamination with AFB1 (5 µg of AFB1/kg feed), AFB1 + Mycosorb® (MTB) 10 g/cow/d, and AFB1 + MTB 50 g/cow/d. In response to the negative control, AFM1 concentrations in milk remained below the limit of detection (<5 ng/kg), whereas cows fed the AFB1-contaminated feed had milk AFM1 concentrations ranging from 110 to 230 ng/kg. At the end of the washout period, AFM1 was again undetectable. The dairy cow model was also used to test the efficacy of the yeast-cell-wall-based mycotoxin binder Mycosorb® (MTB) in reducing secretion of AFM1 into milk by cows fed the same AFB1-contaminated diet. When supplemented at 50 g/head/day, MTB significantly reduced (P < 0.05) AFM1 secretion into milk with no adverse effects on milk production. The dairy cow model is a sensitive tool for measuring aflatoxin transmission to milk and mycotoxin binder efficacy at 5 µg of AFB1/kg feed. As it is common for on-farm AFB1 concentrations to exceed 5 µg/kg, more research may be warranted to determine the effectiveness of the model at higher AFB1 concentrations.

A pilot study was conducted to evaluate the suitability of hepatic aflatoxin (AFB1) concentration as a biomarker to assess the in vivo efficacy of a mycotoxin binder in poultry when AFB1 dietary concentrations are low. Diets containing low doses of AFB1 without or with Mycosorb® (MTB), a mycotoxin binder, were fed to broilers from 7 to 21 days of age. The accumulation of AFB1 in liver was measured by high performance liquid chromatography with a detection limit of 5 ng/kg liver. In response to 10 and 50 µg AFB1/kg feed, hepatic AFB1 accumulation was 27 and 145 ng AFB1/kg liver, respectively. At each dietary concentration of AFB1, the inclusion of 5 g MTB/kg of feed reduced (P < 0.1 for 10 μg AFB1/kg feed and P < 0.05 for 50 μg AFB1/kg feed) hepatic AFB1 accumulation by at least 50%. These results suggest that hepatic AFB1 concentration is a suitable biomarker for evaluating mycotoxin binder efficacy in poultry fed the EU maximum dietary concentration of 10 µg of AFB1/kg feed.

A 3-week-feeding study (1–21 d post-hatch) was conducted to evaluate the efficacy of total curcuminoids (TCMN), as an antioxidant, to ameliorate the adverse effects of aflatoxin B1 (AFB1) in broiler chickens. Turmeric powder (Curcuma longa L.) that contained 2·55 % TCMN was used as a source of TCMN. Six cage replicates of five chicks each were assigned to each of six dietary treatments, which included: basal diet; basal diet supplemented with 444 mg/kg TCMN; basal diet supplemented with 1·0 mg/kg AFB1; basal diet supplemented with 74 mg/kg TCMN and 1·0 mg/kg AFB1; basal diet supplemented with 222 mg/kg TCMN and 1·0 mg/kg AFB1; basal diet supplemented with 444 mg/kg TCMN and 1·0 mg/kg AFB1. The addition of 74 and 222 mg/kg TCMN to the AFB1 diet significantly (P < 0·05) improved weight gain and feed efficiency. Increase (P < 0·05) in relative liver weight in birds fed AFB1 was significantly reduced (P < 0·05) with the addition of 74, 222 and 444 mg/kg TCMN to the AFB1 diet. The inclusion of 222 mg/kg TCMN ameliorated the adverse effects of AFB1 on serum chemistry in terms of total protein, albumin and γ-glutamyl transferase activity. The decreased antioxidant functions due to AFB1 were also alleviated by the inclusion of 222 mg/kg TCMN. It is concluded that the addition of 222 mg/kg TCMN to the 1·0 mg/kg AFB1 diet demonstrated maximum antioxidant activity against AFB1.

The avian kidney has shown a remarkable ability to maintain adequate and even normal function in the face of a mycotoxin challenge. Full evaluation of the nephrotoxicity of a substance must therefore go beyond pathological and ultrastructural documentation and include a complete functional evaluation. To date, only three nephrogenic mycotoxins, citrinin, ochratoxin A, and aflatoxin B1 have been assessed for their ability to alter avian renal function. At non-lethal doses, citrinin appears to have acute reversible effects on the distal portion of the nephron, possibly acting to inhibit water absorption. Ochratoxin A is more potent and less acute than citrinin but less site-specific in that both proximal and distal tubules are damaged, resulting in severe loss of both fluids and electrolytes. Aflatoxin B1 at a dosage and duration which induced hepatotoxicity, concurrently exerted nephrogenic effects such as increased urinary calcium excretion and decreased inorganic phosphate excretion. In commercial broilers aflatoxin B1 has been shown to decrease plasma levels of 25-hydroxy vitamin D, 1,25-dihydroxy vitamin D and may also decrease endogenous parathyroid hormone synthesis and the renal sensitivity to parathyroid hormone. Furthermore, exposure to aflatoxin B1 may cause prolonged alteration in renal function such as reduced glomerular filtration rate. This review summarizes the studies which have been conducted to evaluate avian renal function during both acute and chronic exposure to these three mycotoxins.

Wistar albino female rats were maintained for 10 d on diets containing various levels of the vegetable Solanum nigrum. Simultaneously, they received daily intraperitoneal injections of aflatoxin B1 (AFB1) (either 0.2 or 0.4 mg/kg body-weight) diluted in propylene glycol. At the end of the experiment, all animals were killed and their serum and hepatic microsomes were prepared for assay of enzymes. Results showed that aminopyrine N-demethylase activity increased 2.5-fold with 200 (S200) and 600 (S600) g S. nigrum/kg diets. Activity of uridine diphosphate glucuronyltransferase (UDPGT) (EC 2.4.17) also increased twofold. Similar results were obtained with glutathione S-transferase (EC 2.5.1.18) activity which increased by 60% with diet S600. After AFB1 treatment, a general increase in the activities of the above enzymes was found, except for UDPGT in the group fed on diet S600. When rats were fed on the diet without S. nigrum, AFB1 induced an increase in alkaline phosphatase (ALP) (EC 3. 1. 3. 1), aspartate aminotransferase (AST) (EC 2. 6. 1. 1) and γ-glutamyltransferase (γ-GT) (EC 2. 3. 2. 2) levels in the serum. AFB1 also induced increases in serum ALP and γ-GT levels when rats were fed on diet S600