An evaluation of kapok and Spanish moss bedding materials for mycotoxigenic potential using aspergillus flavus,A. parasiticus,and fusarium tricinctum

The potential of kapok and Spanish moss (used as fill materials in bedding manufacture) to support the production of aflatoxins (AFTs) and/or trichothecenes when inoculated with Aspergillus flavus, A. parasiticus, and Fusarium tricinctum isolates was evaluated. During incubation for 51 days at 23°C, all Spanish moss replicates supported the production of aflatoxins AFB₁ and AFG₁ and 90% supported trichothecene production (T-2 and HT-2 toxins). In 60% of the kapok replicates, production of AFB₁ and AFG₁ was supported, but none supported trichothecene production. In both materials, significantly more AFG₁ was produced than AFB₁ (P < 0·01). AFT production levels were significantly greater (P < 0·01) in Spanish moss in kapok, and ranged from 90 ng AFB₁g⁻¹ kapok to 839 ng AFB₁g⁻¹ Spanish moss and 221 ng AFG₁g⁻¹ kapok to 1376 ng AFG₁g⁻¹ Spanish moss. Spanish moss supported production of 15 271 ngT-2 toxin and 13 034 ng HT-2 toxin g⁻¹ Spanish moss.     

Inhibitory effect of hena (Lawsonia inermis leaves) and carrot root on aflatoxin production byAspergillus parasiticus

Experiments were undertaken to evaluate the effect of some natural products (hena, and carrot root) on growth and aflatoxins production byAspergillus parasiticus FRR 2752. Powdered hena (0.5 and 5%) inhibited mycelial growth and delayed 1 sporulation ofA parasiticus during 7 days. The inhibition of growth was increased with increasing the added amount. Aflatoxins production byA parasiticus was reduced with 40–100% in the presence of hena (Lawsonia inermis leaves). Carrot root extract stimulated the fungal growth and aflatoxin production, whereas carrot root fibers slightly enriched fungal growth, inhibited aflatoxins production (B₁, G₁, and G₂), but there was no inhibition of aflatoxin B₂ production byA parasiticus.     

Isolation and molecular characterization of mycotoxigenic fungi in agarwood

Agarwood (Oudh), is often used by people in the Kingdom of Saudi Arabia. The Oudh has been mentioned in the Hadith and is traditionally used for its aroma (perfuming smell) and potential medicinal applications. The aim of the study was to isolate mycotoxigenic fungi that grow on agarwood and the factors and storage conditions that enhance their growth potential. In addition to the detection of associated mycotoxins like: Aflatoxin B1 (AFB₁) and ochratoxin A (OTA) from agarwood. Agarwood samples were collected from local markets of Jeddah governorate, Kingdom of Saudi Arabia. Standard dilution plate method was used for the isolation of fungi. Isolated fungi were identified based on morphological characteristics and confirmed using molecular biology techniques. AFB₁ and OTA were detected by High Performance Liquid Chromatography (HLPC). The results indicated that the most commonly isolated fungal genera were in the following descending order: Aspergillus, Penicillium, Fusarium and Rhizopus. Among Aspergillus genera, A. flavus and A. ochraceus were detected based on their morphology and confirmed by PCR using specific primers. It was also noted that AFB₁ was released by 15.3 and 55.0% of A. flavus and A. parasiticus isolates respectively with levels reaching up to 14.60 µg/L. The moisture content in the samples ranged from 3% to 10% affected fungal growth. AFB₁ was detected in 22 out of 50 of the samples. The maximum level of AFB₁ (50.7 µg/kg) was detected in samples with higher moisture content (12%) stored at a temperature of 32 °C. Aspergillus fungi were found to be the most predominant fungal genera found on agarwood. Moisture content (9–10%) and storage temperature (32 °C) stimulated fungal growth and their ability to produce mycotoxins. For this reason, storage conditions at the marketing place should be adequate in order not to provide a conducive environment for fungal growth which is associated with the mycotoxin production. In order to prevent fungal growth and mycotoxin production, it would be recommended to store agarwood at temperatures not exceeding 25 °C and moisture content of up to a maximum of 5–6%.     

Aflatoxin B1 and zearalenone in dairy feeds in Portugal, 2009–2011

This paper presents 3 years of data (2009–2011) on the occurrence of two mycotoxins, aflatoxin B₁ (AFB₁) and zearalenone (ZEA), in samples of feedstuff for dairy cows (n?=?963), ewes (n?=?42), and goats (n?=?131) produced in Portugal. AFB₁ was found in 15 samples of cow feed (1.6 %), 3 samples of ewe feed (2.3 %) and in 2 samples of goat feed (4.8 %). All but two samples contained AFB₁ at levels below the European Union maximum level (5 μg/kg). Nearly half (45 %) of the samples were contaminated with ZEA, but its levels were relatively low, at 5–136.9 μg/kg, well below the European Union guidance value (500 μg/kg).     

Aflatoxin B<Subscript>1</Subscript> contamination in feed from Puglia and Basilicata regions (Italy): 5 years monitoring data

During a 5-year period from 2010 to 2014, n = 919 samples of feed and raw materials were analyzed for aflatoxin B₁ (AFB₁) contamination using accredited ELISA screening methods. Only 0.76 % of these samples were non-compliant with maximum levels set by the European Union Regulation 32/2002. Non-compliant samples were mainly from the province of Bari (n = 3 samples, mean AFB₁ value 7.03 μg/kg), although the highest AFB₁ levels were found in two samples from the provinces of Foggia and Brindisi, at 32.6 ± 3.6 μg/kg and 31.0 ± 4.0 μg/kg, respectively. Mean AFB₁ levels in samples contaminated but compliant with the limits ranged from 1.4 to 2.2 μg/kg. Considering the great importance of climate conditions in mycotoxins production, during crops production and during the critical phases of materials storage and/or transport, to better understand the variability in contamination levels, the analytical results were reviewed in term of temperature and relative environmental humidity in the sampling areas. Correlations between aflatoxin B₁ levels in feed and these climate factors might explain seasonal and annual variations in contamination levels. The data from the present study provide useful suggestions for the organization of targeted monitoring plans and the protection of consumers, as well as for improvement in the quality standards of zootechnological activities and feed industry.     

A limited survey of aflatoxin B1 contamination in Indonesian palm kernel cake and copra meal sampled from batches

Samples from large (100–200 tons) batches of palm kernel cake (PKC, n?=?20) and copra meal (CM, n?=?13) were collected at production facilities of four Indonesian feed mill manufacturers and analysed for aflatoxin B₁ (AFB₁) by ELISA. Recoveries using spiked samples ranged from 86 to 113 %, with relative standard deviations of <9 % (PKC) and <6 % (CM). All batches were positive for AFB₁: in PKC, at levels of 5.8–93.1 μg/kg (mean 49 μg/kg), and in CM, at levels of 1.1–147 μg/kg (mean 38.1 μg/kg). AFB₁ levels were, in most batches, below the maximum level (100 μg/kg) recommended by the National Standardisation Agency, Republic of Indonesia. However, about half of the batches exceeded both the European Union and USA regulations for AFB₁ in animal feed. In conclusion, serious efforts are necessary to control production, storage and shipment of palm kernel cake and copra meal for feed purposes, and clearly not only for products intended for export but also to reduce AFB₁ levels in domestic Indonesian feed.     

Effects of Heracleum persicum ethyl acetate extract on the growth, hyphal ultrastructure and aflatoxin biosynthesis in Aspergillus parasiticus

The ethyl acetate extract of leaves, seeds and flowers of Heracleum persicum, a medicinal plant of Iran (family Apiaceae) inhibited growth and aflatoxin (AF) production of Aspergillus parasiticus. On the basis of total dry weight growth inhibition by the leaf extract ranged from 17.1 to 36.9 %, by the flower extract from 32.2 to 75.6 %, and by the seed extract from 27.5 to 74.9 %. Production of AFB₁ and AFG₁ was inhibited in a dose-dependent manner, with a reduction of 88.5–100 % at the highest concentration of 8,000 μg/ml tested. The flower extract decreased ergosterol content of hyphae most significantly. Electron microscopy further revealed structural defects in the treated A. parasiticus including disruption of cytoplasmic membranous compartments, detachment of plasma membrane from the cell wall, and disorganization of hyphal compartments. Collapsed hyphae without conidiation, shorter branches and undifferentiated hyphal tips were also evident. The results indicate that H. persicum extract exerts antifungal and anti-AF activities by disrupting plasma membrane integrity and permeability mainly through interference with ergosterol biosynthesis. These results show that H. persicum can serve as a potent and safe alternative for inhibiting toxigenic aspergilli growth and thus preventing AF contamination of foods and feeds.     

Inhibitory Effects of Ephedra major Host on Aspergillus parasiticus Growth and Aflatoxin Production

This study was undertaken to evaluate the effect of Ephedra major Host, an important medicinal plant with various biological activities, on growth and aflatoxin (AF) production by Aspergillus parasiticus NRRL 2999. The fungus was cultured in yeast extract-sucrose (YES) broth, a conductive medium that supports AF production, in the presence of various concentrations of essential oil (EO), hexanic and methanolic extracts of plant aerial parts, fruits, and roots using microbioassay technique. After incubating for 96 h at 28°C in static conditions, mycelial dry weight was determined as an index of fungal growth, and aflatoxin B₁ (AFB₁) was measured using HPLC technique. Based on the obtained results, EO of plant aerial parts significantly inhibited fungal growth at the highest concentration of 1000 μg/ml without any obvious effect on AFB₁ production at all concentrations used. Among plant extracts tested, only methanolic extract of aerial parts and roots were found to inhibit fungal growth and AFB₁ production dose-dependently with an IC₅₀ value of 559.74 and 3.98 μg/ml for AFB₁, respectively. Based on the GC/MS data, the major components of E. major EO were bis (2-ethylhexyl) phthalate (42.48%), pentacosane (20.94%), docosane (14.64%), citronellol (5.15%), heptadecan (4.41%), cis-3-Hexen-1-ol benzoate (4.07%), and 7-Octen-2-ol (3.25%). With respect to the potent inhibition of fungal growth and AF production by E. major, this plant may be useful in protecting crops from both toxigenic fungal growth and AF contamination.     

Examination of fungal growth and aflatoxin production on marihuana

Under favorable growth conditions,Aspergillus flavus andA. parasiticus produced aflatoxins on marihuana. Cultures ofA. flavus ATCC 15548 produced both aflat oxin B₁(AFB₁) and G₁(AFG₁). The production of AFG₁ was substantially greater than that of AFB₁. Cultures ofA. flavus NRRL 3251 andA. parasiticus NRRL 2999 produced only AFB₁. All natural flora cultures tested negative for aflatoxins. NoAspergilli sporulations were observed in these cultures. In the cultures inoculated with known toxigenic fungi, the highest mean level for total aflatoxins was 8.7 g/g of medium. Marihuana appears not to yield large quantities of these mycotoxins but sufficient levels are present to be a potential health hazard for both the user and the forensic analyst who is in daily contact with such plant material. Careful processing, storage, and sanitation procedures should be maintained with marihuana. If these conditions are disregarded due to the illicit status of marihuana, the potential for mycotoxin contamination must be considered.     

Enzymes in atlatoxin B1 biosynthesis: Strategies for identifying pertinent genes

Recent work on the aflatoxin biosynthetic pathway is reviewed, with special emphasis on the enzymes of the late stages of the pathway involving conversion of sterigmatocystin (ST) to aflatoxin B₁ (AFB₁) through an O-methylsterigmatocystin intermediate. Two enzyme activities were discovered in subcellular fractions of cell-free extracts of a mutant strain ofAspergillus parasiticus (SRRC 163): 1)A post-microsomal methyltransferase (MT) catalyzed conversion of ST to OMST, and 2) a microsomal-associated activity (oxido-reductase) converted OMST to AFB₁. The 168 KDa, anionic MT was purified to homogeneity and characterized (two subunits, 110 KDa and 58 KDa). Preliminary evidence indicated the presence of a cationic isozyme of the MT in mycelial extracts. The oxido-reductase has been partially purified and characterized. Polyclonal antibodies were prepared to the anionic MT and the enzyme's amino acid composition determined. A cDNA library has been constructed from mRNA isolated fromAspergillus parasiticus mycelia during the onset of AFB₁ biosynthesis for the purpose of identifying the genes responsible for aflatoxin biosynthesis.     

Production of aflatoxin byAspergillus parasiticus and its control

The aim of the present work was to investigate the production of aflatoxin byAspergillus parasiticus and to find out the possible ways to control it. Of 40 food samples collected from Abha region, Saudi Arabia, only 25% were contaminated with aflatoxins. Oil-rich commodities had the highly contaminated commodities by fungi and aflatoxins while spices were free from aflatoxins.Bacillus megatertum andB cereus were suitable for microbiological assay of aflatoxins. Czapek’s-Dox medium was found a suitable medium for isolation of fungi from food samples. The optimal pH for the growth ofA. parasiticus and its productivity of aflatoxin B₁ was found at 6.0, while the best incubation conditions were found at 30°C for 10 days. D-glucose was the best carbon source for fungal growth, as well as aflatoxin production. Corn steep liquor, yeast extract and peptone were the best nitrogen sources for both fungal growth and toxin production (NH₄)₂HPO₄ (1.55 gL^-1) and NaNO₂ (1.6 gL^-1) reduced fungal growth and toxin production with 37.7% and 85%, respectively. Of ten amino acids tested, asparagine was the best for aflatoxin B₁ production. Zn²⁺ and Co²⁺ supported significantly both fungal growth, as well as, aflatoxin B₁ production at the different tested concentrations. Zn²⁺ was effective when added toA. parasiticus growth medium at the first two days of the culture age. The other tested metal ions expressed variable effects depending on the type of ion and its concentration. Water activity (a_w) was an important factor controlling the growth ofA. parasiticus and toxin production. The minimum a_w for the fungal growth was 0.8 on both coffee beans and rice grains, while a_w of 0.70 caused complete inhibition for the growth and aflatoxin B₁ production. H₂O₂ is a potent inhibitor for growth ofA. parasiticus and its productivity of toxins. NaHCO₃ and C₆H₅COONa converted aflatoxin B₁ to water-soluble form which returned to aflatoxin B₁ by acidity. Black pepper, ciliated heath, cuminum and curcuma were the most inhibitory spices on toxin production. Glutathione, quinine, EDTA, sodium azide, indole acetic acid, 2,4-dichlorophenoxy acetic acid, phenol and catechol were inhibitory for both growth, as well as, aflatoxin B₁ production. Stearic acid supported the fungal growth and decreased the productivity of AFB₁ gradually. Lauric acid is the most suppressive fatty acid for both fungal growth and aflatoxin production, but oleic acid was the most potent supporter. Vitamin A supported the growth but inhibited aflatoxin B₁ production. Vitamins C and D₂ were also repressive particularly for aflatoxin production The present study included studying the activities of some enzymes in relation to aflatoxin production during 20-days ofA. parasiticus age in 2-days intervals. Glycolytic enzymes and pyruvate-generating enzymes seems to be linked with aflatoxin B₁ production. Also, pentose-phosphate pathway enzymes may provide NADPH for aflatoxin B₁ synthesis. The decreased activities of TCA cycle enzymes particularly from 4th day of growth up to 10th day were associated with the increase of aflatoxin B₁ production. All the tested enzymes as well as aflatoxin B₁ production were inhibited by either catechol or phenol.     

Exposure to aflatoxin B<Subscript>1</Subscript> in Thailand by consumption of brown and color rice

This study assessed the aflatoxin B₁ (AFB₁) intake of the Thai population through consumption of contaminated brown and color rice. A total of 240 rice samples from two harvesting periods were collected in June/July 2012 (period I) and in December 2012/January 2013 (period II) and analyzed for AFB₁ by HPLC with fluorescence detection (limit of detection (LOD)?=?0.093 ng/g). Exposure assessment was based on AFB₁ levels in rice and food intake data for rice according to Thai National Consumption. Frequency and levels of AFB₁ were higher in period I (59 %, <LOD?=?26.61 μg kg^?1) than in period II (10 %, <LOD?=?3.51 μg kg^?1). Only one sample exceeded the Thai standard limit for total aflatoxin of 20 μg kg^?1, but 12 out of 240 rice samples exceeded the European Union maximum level for AFB₁ of 2 μg kg^?1. The data showed that the quality and safety of Thai rice largely comply with the requirement for both exports and domestic consumption. According to the Thai National Consumption data, the estimated AFB₁ intake via rice consumption in period I and period II was 0.80 and 0.12 μg kg^?1 bw day^?1, respectively. The potential risk for cancer, based on the recommendation of the JECFA, was estimated to be 0.011 person/year/100,000 people at a mean consumption. Although the risk via consumption of Thai rice seems to be low, the maximum levels of AFB₁ in this staple food suggest that careful monitoring and surveillance of AFB₁ contamination in rice is essential to ensure the safety of rice.     

The effects of aflatoxin B1 on growth hormone regulated gene-1 and interaction between DNA and aflatoxin B1 in broiler chickens during hatching

Many types of aflatoxin cause problems for both public and animal health. Aflatoxin B₁ (AFB₁) is the most toxic and commonly encountered fungal toxin that appears in poultry feed and in feeds stored under unsuitable conditions. AFB₁ decreases feed quality, egg production and fertility of hatching eggs. Also, AFB₁ alters the development of embryos by infecting eggs. We investigated using sequence analysis the changes caused by different concentrations of AFB₁ on the promoter sequences of the growth hormone regulated gene-1 (GHRG-1) in chick embryo at 13, 17, 19 and 21 days incubation. DNA isolated from the liver of chick embryos treated with different concentrations of AFB₁ was separated using agarose gel electrophoresis to detect apoptosis, and DNA interaction with AFB₁ was investigated using plasmids to detect changes in electrophoretic mobility and their effects on DNA. Base changes of the promoter sequences of GHRG-1 in 5 ng/egg, 15 ng/egg and 40 ng/egg doses of AFB₁ were increased on day 19 compared to base changes of the same AFB₁ doses on day 13. We also found that AFB at different concentrations changed the mobility of DNA by binding to it, and that high doses of AFB1 destroyed DNA. The DNA interaction study using plasmid demonstrated that AFB₁ at high doses was bound to plasmid DNA, slowed its mobility and inhibited restriction cuts.     

Use of yeast (<Emphasis Type="Italic">Pichia kudriavzevii</Emphasis>) as a novel feed additive to ameliorate the effects of aflatoxin B<Subscript>1</Subscript> on broiler chicken performance

The aim of this study was to evaluate the efficacy of autochthonous Pichia kudriavzevii as a novel bioadsorbent for aflatoxin B₁ (AFB₁). The selection of this yeast was based on the AFB₁ adsorption capacity previously demonstrated in vitro (Magnoli et al. 2016). One-day-old Cobb broilers (n = 160) were randomly assigned to four dietary treatments (T1: basal diet (B); T2: B + 0.1% yeast; T3: B + AFB₁, 100 μg/kg; T4: B + 0.1% yeast + AFB₁, 100 μg/kg). Performance parameters (average daily weight gain body, average daily consumption, feed conversion ratio, carcass weight, and dead weight), biochemical parameters (albumin, globulin, and albumin/globulin), liver pathological changes, and AFB₁ residual levels in the liver and excreta were evaluated. Significant differences (P < 0.05) in performance parameters were observed among treatments and controls: T3 group showed the lowest average daily body weight gain value while in T4 group, the value of this parameter increased significantly (P < 0.05). T3 and T4 groups showed the lowest and highest values for average daily feed consumption, respectively. The feed conversion ratio (FC) showed no significant differences among treatments. T3 group showed the lowest dead weight and carcass weight compared with T1 group. The biochemical parameters showed no significant differences among treatments. T3 group showed macroscopic and microscopic liver changes compared to the control. Aflatoxin B₁ levels (μg/g) were detected in broiler livers and showed significant differences among treatments (P < 0.05). In conclusion, native P. kudriavzevii incorporation (0.1%) in broiler diets containing AFB₁ was shown to be effective in ameliorating the adverse effects of AFB₁ on production.     

Comparison of growth and aflatoxin B1 production profiles of Aspergillus flavus strains on conventional and isogenic GM-maize-based nutritional matrices

Maize grown in both North and South America are now predominantly genetically modified (GM) cultivars with some resistance to herbicide, pesticide, or both. There is little information on the relative colonisation and aflatoxin B₁ (AFB₁) production with maize meal-based nutritional matrices based on kernels of non-GM maize and isogenic GM-ones by strains of Aspergillus flavus. The objectives were to examine the effect of interacting conditions of temperature (25–35 °C) and water availability (0.99–0.90 water activity, a_w) on (a) mycelial growth, (b) AFB₁ production and (c) develop contour maps of optimum and marginal conditions of these parameters for four strains of A. flavus on three different non-GM and isogenic GM-maize based nutritional media. The growth of the four strains of A. flavus (three aflatoxigenic; one non-aflatoxigenic) was relatively similar in relation to the temperature × a_w conditions examined on both non-GM and GM-based matrices. Optimum growth overall was at 30–35 °C and 0.99 a_w for all four strains. Under water stress (0.90 a_w) growth was optimum at 35 °C. Statistically: non-GM, GM cultivars, temperature and a_w all significantly affected growth rates. For AFB₁ production, all single and interacting factors were statistically significant except for non-GM × GM cultivar. In conclusion, colonisation of GM- and non-GM nutritional sources was similar for the different A. flavus strains examined. The contour maps will be very useful for understanding the ecological niches for both toxigenic and non-toxigenic strains in the context of the competitive exclusion of those producing aflatoxins.     

Aflatoxin-lysine adducts in blood serum of the Malawian rural population and aflatoxin contamination in foods (groundnuts,maize) in the corresponding areas

Aflatoxin-lysine (AFB₁-lys) adduct levels in blood samples collected from 230 individuals living in three districts of Malawi (Kasungu, Mchinji, and Nkhotakota) and aflatoxin B₁ (AFB₁) levels in groundnut and maize samples collected from their respective homesteads were determined using indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) methods. AFB₁-lys adducts were detected in 67% of blood samples, with a mean concentration of 20.5?±?23.4 pg/mg of albumin. AFB₁ was detected in 91% of groundnut samples and in 70% of maize samples, with mean AFB₁ levels of 52.4 and 16.3 μg/kg, respectively. All participants of this study reported consuming maize on a daily basis and consuming groundnuts regularly (mean consumption frequency per week: 3.2?±?1.7). According to regression analysis, a frequency of groundnut consumption of more than four times per week, being female, and being a farmer were significant (p?<?0.05) contributors to elevated AFB₁-lys adduct levels in the blood. This is the first report on AFB₁-lys adducts in blood samples of residents in Malawi. The results reinforce the urgent need for interventions, aiming at a reduction of aflatoxin exposure of the population.     

Determination of serum aflatoxin B<Subscript>1</Subscript>-lysine to evaluate the efficacy of an aflatoxin-adsorbing feed additive in pigs fed an aflatoxin B<Subscript>1</Subscript>-contaminated diet

In this study, serum aflatoxin B₁ (AFB₁)-lysine was determined in order to evaluate the in vivo efficacy of a hydrated sodium calcium aluminosilicate (HSCAS) in pigs fed AFB₁. Twenty-four 49-day-old crossbred barrows were maintained in individual cages and allowed ad libitum access to feed and water. A completely randomized design was used with six animals assigned to each of four dietary treatments for 21 days as follows: (A) basal diet (BD), (B) BD supplemented with 0.5 % HSCAS, (C) BD supplemented with 1.1 mg/kg AFB₁, and (D) BD supplemented with 0.5 % HSCAS and 1.1 mg/kg AFB₁. HSCAS was able to alleviate the toxic effects of AFB₁ on pigs and reduce (P < 0.05) the levels of serum AFB₁-lysine. Cumulative reductions of adduct yield values, calculated through the equation [(pg AFB₁-lysine/mg albumin) / (μg AFB₁/kg body weight)], were 53.0, 62.8, and 72.1 after 7, 14, and 21 days of oral exposure, respectively. AFB₁-lysine has potential as an AFB₁-specific biomarker for diagnostic purposes and for evaluating the efficacy of chemoprotective interventions in pigs.     

Aflatoxin B1 affects feed consumption in male rats through an action on the central nervous system

Aflatoxins (AFTs), secondary metabolites of the biodeteriogens Aspergillus flavus and A. parasiticus, include aflatoxin B₁ (AFB₁), which is hepatocarcinogenic, can cause cellular and tissue damage and because its chemical composition is similar to that of certain steroids, may exhibit some pathological activities similar to those of steroids. The latter can suppress feed consumption by acting upon the central nervous system. Here, is reported the results of an investigation designed to assess whether this biodeteriogen could alter either feed consumption or plasma glucose levels. Male Sprague-Dawley rats maintained for two weeks upon laboratory rat chow were subjected to either intracerebroventricular (ICV) or intravenous (IV) injections of both AFB₁ and estradiol. Both non-injected and carrier-injected (0·9% NaCl) animals served as controls. Following fasting for 21 h, the rats were provided with a weighed amount of feed and both feed consumption and plasma glucose levels quantified during the 22nd, 23rd and 24th hour. Both ICV injections of 10 and 100 ng AFB₁ and IV injections of 1 and 10 μg AFB₁ kg⁻¹ significantly (p < 0·01) suppressed daily feed intake, but did not affect plasma glucose levels. This supports the hypothesis that AFB₁ suppresses feed intake probably through action upon the central nervous system. If true, this action as well as the toxic and carcinogenic aspects, further support the need for the prevention and/or removal of the mycotoxin from food and feed.     

Effect of UV irradiation on aflatoxin reduction: a cytotoxicity evaluation study using human hepatoma cell line

In this proof-of-concept study, the efficacy of a medium-pressure UV (MPUV) lamp source to reduce the concentrations of aflatoxin B₁, aflatoxin B₂, and aflatoxin G₁ (AFB_1, AFB₂, and AFG₁) in pure water is investigated. Irradiation experiments were conducted using a collimated beam system operating between 200 to 360 nm. The optical absorbance of the solution and the irradiance of the lamp are considered in calculating the average fluence rate. Based on these factors, the UV dose was quantified as a product of average fluence rate and treatment time. Known concentrations of aflatoxins were spiked in water and irradiated at UV doses ranging from 0, 1.22, 2.44, 3.66, and 4.88 J cm^?2. The concentration of aflatoxins was determined by HPLC with fluorescence detection. LC-MS/MS product ion scans were used to identify and semi-quantify degraded products of AFB₁, AFB₂, and AFG₁. It was observed that UV irradiation significantly reduced aflatoxins in pure water (p < 0.05). Irradiation doses of 4.88 J cm^?2 reduced concentrations 67.22% for AFG₁, 29.77% for AFB₂, and 98.25% for AFB₁ (p < 0.05). Using this technique, an overall reduction of total aflatoxin content of ≈95% (p < 0.05) was achieved. We hypothesize that the formation of ˙OH radicals initiated by UV light may have caused photolysis of AFB₁, AFB₂, and AFG₁ molecules. In cell culture studies, our results demonstrated that the increase of UV dosage decreased the aflatoxin-induced cytotoxicity in HepG₂ cells. Therefore, our research finding suggests that UV irradiation can be used as an effective technique for the reduction of aflatoxins.     

Mycotoxigenic fungi and mycotoxins associated with stored maize from different regions of Lesotho

Samples of stored maize from villages located in five different agroecological zones (southern lowlands, northern lowlands, Senqu river valley, foothills and mountains) of Lesotho were collected in 2009/10 and 2010/11 and assessed for contamination with toxigenic fungi. The water activity of all samples collected during the two seasons was <0.70. The total fungal populations of the maize from different regions in the two seasons was not significantly different (p?>?0.05). Fusarium verticillioides, F. proliferatum and F. subglutinans predominated in different regions in both seasons based on molecular analyses. In the 2009/10 season, the isolates of these species all produced FB₁, while in the 2010/11 season, very few produced FB₁. A. flavus isolates (2009/10) were recovered from mountains and Senqu river valley samples while the 2010/11 isolates were predominantly from the foothills and northern lowlands. The mountain isolates of Aspergillus section Flavi produced the highest levels of AFB₁ (20 mg kg^?1). Aspergillus parasiticus was only isolated from the foothills, Senqu river valley and southern lowlands samples, and the AFB₁ levels produced ranged from ‘none detected’ to 3.5 mg kg^?1. The Aspergillus ochraceous isolates were least frequently encountered in both seasons. In the 2009/10 season, the isolates from the northern lowlands produced ochratoxin A (OTA) in culture. No isolates of A. niger from different regions in both seasons produced any OTA. Multi-mycotoxin analyses of the maize samples were done for a range of mycotoxins. At least one sample from each region in both seasons was FB₁-positive. FB₁ levels for 2010/11 samples (7–936 μg kg^?1) were higher than in the 2009/10 season (2–3 μg kg^?1). In both seasons, the mountains registered the highest levels of FB₁. Deoxynivalenol (DON) was recovered from all the samples analysed, with the highest mean contamination of 1,469 μg kg^?1 in samples from the northern lowlands. Moniliformin (MON) was detected from all agroecological zones in the two seasons (5–320 μg kg^?1 in 2009/10; 15–1,205 μg kg^?1 in 2010/11). Emerging toxins such as fusaproliferin (FUS) and beauvericin (BEA) were also detected. OTA was not detected in any of the samples analysed. Only one 2009/10 sample in the Senqu river valley was positive for AFB₁. This is the first report on toxigenic fungi and multi-mycotoxin contamination of maize samples from subsistence farmers’ stores in different agroecological zones of Lesotho.