Screening of Aflatoxins and Zearalenone in feedstuffs and complete feeds for pigs in Southern Vietnam

Public health risk due to aflatoxin and fumonisin contamination in rice in the Mekong Delta, Vietnam

Mycotoxin contamination in rice can lead to a health risk for consumers. In this study, the health risk among different age groups of Vietnamese population in the Mekong Delta, Vietnam was evaluated through rice consumption. Total aflatoxins (AFs) and fumonisins (FBs) in raw rice samples (n = 50) were analyzed using an ELISA method. A survey (n = 155) was used to collect data on rice consumption and consumer practices for the evaluation of mycotoxin exposure. Results showed that the frequency of AFs and FBs contamination was 60 and 74% with the average concentrations in raw rice ranging from 1.88–4.00 ng/g and 227–290 ng/g from the lower bound (LB) to the upper bound (UB), respectively. The average AFs exposure due to rice consumption was estimated from 0.81 to 2.44 ng/kg bw/day at scenarios LB – UB with the medium bound (MB) of 2.10, 1.60, 1.92 and 1.23 ng/kg bw/day for children, adolescents, adults and elderly, respectively. These values ranged from 343 to 724 ng/kg bw/day with respect to FBs (scenarios LB - UB), which are below the provisional maximum tolerable daily intakes (PMTDI) value (2000 ng/kg bw/day). The margin of exposure (MoE) to AFs ranged from 160 to 1585,179-2669,149–2175 and 206–3480 for children, adolescent, adults and elderly, respectively from UB - LB, indicating a high health risk for this carcinogenic hazard since the values are so lower than 10,000 (safe limit). However, for FBs, MoE value ranged from 105 to 575 (UB-LB) for all groups, which are higher compared to 100 (safe limit), indicating no risk for public health. The mean cancer risk due to estimated AFs exposure at LB - UB was 0.05–0.13 cases/year/100,000 individuals with MB of 0.08–0.13 cases/year/100,000 people for all four age groups. This study provides new insights into probabilistic risk assessment and potential health impact of mycotoxins in rice in the Mekong Delta, Vietnam.

The Occurrence and Co-Occurrence of Regulated, Emerging, and Masked Mycotoxins in Rice Bran and Maize from Southeast Asia

Raw feed materials are often contaminated with mycotoxins, and co-occurrence of mycotoxins occurs frequently. A total of 250 samples i.e., rice bran and maize from Cambodia, Laos, Myanmar, and Thailand were analysed using state-of-the-art liquid chromatography-mass spectrometry (LC-MS/MS) for monitoring the occurrence of regulated, emerging, and masked mycotoxins. Seven regulated mycotoxins – aflatoxins, ochratoxin A, fumonisin B₁, deoxynivalenol, zearalenone, HT-2, and T-2 toxin were detected as well as some emerging mycotoxins, such as beauvericin, enniatin type B, stachybotrylactam, sterigmatocystin, and masked mycotoxins, specifically zearalenone-14-glucoside, and zearalenone-16-glucoside. Aspergillus and Fusarium mycotoxins were the most prevalent compounds identified, especially aflatoxins and fumonisin B₁ in 100% and 95% of samples, respectively. Of the emerging toxins, beauvericin and enniatin type B showed high occurrences, with more than 90% of rice bran and maize contaminated, whereas zearalenone-14-glucoside and zearalenone-16-glucoside were found in rice bran in the range of 56–60%. Regulated mycotoxins (DON and ZEN) were the most frequent mycotoxin combination with emerging mycotoxins (BEA and ENN type B) in rice bran and maize. This study indicates that mycotoxin occurrence and co-occurrence are common in raw feed materials, and it is critical to monitor mycotoxin levels in ASEAN’s feedstuffs so that mitigation strategies can be developed and implemented.

Development of a reliable UHPLC-MS/MS method for simultaneous determination of zearalenone and zearalenone-14-glucoside in various feed products

A reliable ultra-high-performance liquid chromatography–tandem mass spectrometry method (UHPLC-MS/MS) was developed for the simultaneous determination of two mycotoxins, that is, zearalenone (ZEN) and zearalenone-14-glucoside (ZEN-14G) in formula feed, concentrated feed, and premixed feed products. An improved sample pretreatment was achieved with the hydrophilic–lipophilic balance (HLB) cartridges efficiently removing the impurities and enriching the target analytes in different feeds. The critical parameters affecting the performance of the solid-phase extraction (SPE) procedure were carefully optimized, and 20% acetonitrile in water as the loading solution, 50% methanol in water as the washing solvent, and 5 ml of methanol as the elution solvent yielded the optimal purification efficiencies. The established method was thoroughly validated in terms of linearity (R² ≥ 0.999), sensitivity (limit of quantification in the range of 0.50–5.00 μg kg⁻¹), recovery (89.35 ± 2.67% to 110.93 ± 1.56%), and precision (RSD, 3.00–14.20%), and it was then successfully applied to investigate a total of 60 feed samples. Among them, 50 samples were found to be contaminated with ZEN (an incidence of 83.3%) at levels ranging from 0.63 to 615.24 μg kg⁻¹, whereas 22 samples were contaminated with ZEN-14G (an incidence of 36.7%) in the range of 0.89–15.31 μg kg⁻¹. The developed method proved to be a specific and reliable tool for intensive monitoring of ZEN and ZEN-14G in complex feed matrices.

Occurrence and exposure assessment of aflatoxins in Zhejiang province, China

The purpose of this study was to assess the risk of aflatoxins due to multiple food consumption among the Zhejiang population. Ultra-high-performance liquid chromatography coupled with tandem mass spectrometry method was used to determine aflatoxins in 792 samples. Aflatoxins were detected in 27.1% of the samples at levels between 0.07 and 262.63 μg kg^-1, and aflatoxins B₁ was the most frequently detected among different types of samples. 0.8% of peanut oil, 3.39% of nut products as well as 1.1% of condiments contaminated with aflatoxins B₁ exceeded China national tolerance limits. Peanut oil had the highest incidence of aflatoxin, with a range from 0.17 to 22.50 μg kg^-1. Using bags conferred limited advantages in reducing aflatoxin contents. Moreover, peanut and rice were the main contributors to dietary exposure to aflatoxins among Zhejiang residents. Finally, the margin of exposure values obtained by rice consumption were far from the safe margin of 10,000, indicating a potential risk to public health. The results pointed out the need for further prioritization of aflatoxins B₁ risk-management actions in Zhejiang.

Anti-mycotoxigenic properties of probiotic Bacillus spp. in Japanese quails

The current study was conducted to evaluate the anti-mycotoxigenic effects of previously isolated Bacillus spp. in Japanese quails. A total of 240-day-old Japanese quails were assigned in to six treatments and four replicates. Dietary treatments included the following: negative control (basal diet), positive control (basal diet + 2.5 ppm afltatoxin B₁), probiotic treatments (basal diet + 2.5 ppm afltatoxin B₁), and 10⁸ cfu/ml of different Bacillus spp. (B. megaterium, B. subtilis, or B. laterosporus) in drinking water and treatment P (basal diet + 2.5 ppm afltatoxin B₁ and 2.5 ppm Polysorb®). Body weight gain, feed intake, and feed conversion ratio were not affected by dietary treatments (P > 0.05). Carcass yield significantly increased in B. megaterium and B. subtilis treatments compared with positive control. Supplementation of B. megaterium significantly increased testes, uterus and oviduct weights, skin response to 2,4-dinitro 1-chlorobenzene and phytohemagglutinin, and antibody production against sheep red blood cells (P < 0.05). B. megaterium could significantly increase bursa weight and decrease liver weight compared with positive control (P < 0.05). B. megaterium, B. laterosporus, and Polysorb treatments significantly decreased H:L and aspartate aminotransferase activity in aflatoxin B₁ fed control (P < 0.05). B. megaterium and B. laterosporus significantly increased tibia weight, length, radius, index, and ash content compared with positive control (P < 0.05). All dietary additives significantly reduced meat oxidation, total aerobic bacteria, and spore forming bacteria of ileal content compared with positive control (P < 0.05). Ileal lactic acid bacteria significantly increased in B. megaterium treatment (P < 0.05). Totally, B. megaterium might be a promising probiotic with a comparable afltatoxin B₁ removal potential to commercial toxin binder (Polysorb).

Effects of mycotoxin-contaminated feed on farm animals

Mycotoxins are secondary products produced by fungi in cereals and are frequently found in the livestock industry as contaminants of farm animal feed. Studies analyzing feed mycotoxins have been conducted worldwide and have confirmed the presence of mycotoxins with biological activity, including aflatoxin, ochratoxin A, fumonisin, zearalenone, and deoxynivalenol, in a large proportion of feed samples. Exposure to mycotoxins can cause immunotoxicity and impair reproductive function in farm animals. In addition, exposure of tissues, such as the kidneys, liver, and intestines, to mycotoxins can exert histopathological changes that can interfere with animal growth and survival. This review describes previous studies regarding the presence of major mycotoxins in the feed of farm animals, especially pigs and poultry. Moreover, it describes the adverse effects of mycotoxins in farm animals following exposure, as well as the biological activity of mycotoxins in animal-derived cells. Mycotoxins have been shown to regulate signaling pathways, oxidative stress, endoplasmic reticulum stress, apoptosis, and proliferation in porcine and bovine cells. A clear understanding of the effects of mycotoxins on farm animals will help reduce farm household economic loss and address the health concerns of people who consume these meat and dairy products.

Determination of Aflatoxin B1 in Feedstuffs without Clean-Up Step by High-Performance Liquid Chromatography

A reliable and rapid method has been developed for the determination of aflatoxin B1 (AFB1) in four kinds of feedstuffs comprising broken rice, peanuts, corn, and fishmeal. A sample preparation was carried out based on the QuEChERS method with the exclusion of the clean-up step. In this study, AFB1 was extracted using acetonitrile/methanol (40/60 v/v), followed by partitioning with sodium chloride and magnesium sulfate. High-performance liquid chromatography with precolumn derivatization and fluorescence detection was performed. The coefficients of determination were greater than 0.9800. Throughout the developed method, the recovery of all feedstuffs achieved a range of 82.50-109.85% with relative standard deviation lower than 11% for all analytes at a concentration of 20-100 ng/g. The limit of detection (LOD) ranged from 0.2 to 1.2 ng/g and limit of quantitation (LOQ) ranged from 0.3 to 1.5 ng/g. The validated method was successfully applied to a total of 120 samples. The occurrence of AFB1 contamination was found at the following concentrations: in broken rice (0.44-2.33ng/g), peanut (3.97-106.26ng/g), corn (0.88-50.29 ng/g), and fishmeal (1.06-10.35 ng/g). These results indicate that the proposed method may be useful for regularly monitoring AFB1 contamination in feedstuffs.

An investigation into aflatoxin M 1 in slaughtered fattening pigs and awareness of aflatoxins in Vietnam

BACKGROUND

Aflatoxin M1 (AFM1) is a hydroxylated metabolite formed after aflatoxin B1 (AFB1) is consumed by humans and animals; it can be detected in urine, milk and blood. It is well recognized that AFB1 is toxic to humans and other animals. The International Agency for Research on Cancer (IARC) classifies aflatoxins as group 1 carcinogens and AFM1 as group 2B carcinogen. The main objective of this study was to evaluate the exposure of pigs to aflatoxins as well as to assess the public awareness of aflatoxins among people in five provinces in Vietnam.

RESULTS

A total of 1920 urine samples were collected from slaughterhouses located in five provinces. Overall, the positive rate of AFM1 was 53.90% (95% confidence interval 51.64-56.15) using a cut-off of 0.15 μg/kg (range: limit of detection to 13.66 μg/kg, median: 0.2 μg/kg and mean: 0.63 μg/kg). A total of 252 people from the general population were interviewed from 5 provinces, and overall 67.86% reported being aware of aflatoxins. We also found that men and more highly educated had significantly increased awareness of aflatoxins compared to the females and primary/secondary school group. The respective odds ratios (ORs) were as follows: "male" group (OR: 2.64), "high school educated" group (OR: 3.40) and "college/university or more educated" group (OR: 10.20).

CONCLUSIONS

We can conclude that pigs in Vietnam are exposed to aflatoxins to varying degrees, and there may be a risk that pork products could contain AFM1. Further investigation is needed into the possible health impacts as well as to aid in establishing regulations for animal feed to reduce the health impacts in humans and animals.

A survey of aflatoxin B1 in maize and awareness of aflatoxins in Vietnam

Vietnam is a tropical country with high temperature and precipitation, which may provide good conditions for fungal growth. A few limited studies have been conducted to evaluate the level of aflatoxin B1 in maize in Vietnam. In addition, no studies have been conducted to evaluate the perception and knowledge of aflatoxins in Vietnam. Therefore, the main objective of this study was to determine the levels of aflatoxin B1 for human and animal consumption in maize and evaluate perceptions and knowledge of aflatoxins among people across the country. A total of 2,370 samples were collected from six provinces and analysed using ELISA. Among collected samples, 799 samples (33.71%, 95% confidence interval (CI): 31.81-35.66%) and 687 samples (28.98%, 95%CI: 27.17-30.86%) had levels above 2 µg/kg and 5 µg/kg, respectively [range from below limit of detection (LOD) to 34.8 µg/kg; of the samples above LOD, the mean was 13.1 µg/kg and median was 11.2 µg/kg]. A total of 551 people were interviewed from 6 provinces. The survey showed that awareness of aflatoxins (question: Have you heard about aflatoxins?) in southern Vietnam [An Giang (25%), Dak Lak (23.23%) and Dong Nai (6%)] was relatively higher than in provinces in northern Vietnam. We believe that this analysed information can be useful to better understand the epidemiology of aflatoxins in different provinces. This study also produces evidence on potential risk to humans and animals in Vietnam as well as demographic factors (such as gender and level of education) significantly influencing knowledge of aflatoxins. In conclusion, this paper points to the importance of raising the awareness of the risks with aflatoxins, bearing in mind the gender aspect during capacity development.

Procarcinogens - Determination and Evaluation by Yeast-Based Biosensor Transformed with Plasmids Incorporating RAD54 Reporter Construct and Cytochrome P450 Genes

In Vietnam, a great number of toxic substances, including carcinogens and procarcinogens, from industrial and agricultural activities, food production, and healthcare services are daily released into the environment. In the present study, we report the development of novel yeast-based biosensor systems to determine both genotoxic carcinogens and procarcinogens by cotransformation with two plasmids. One plasmid is carrying human CPR and CYP (CYP3A4, CYP2B6, or CYP2D6) genes, while the other contains the RAD54-GFP reporter construct. The three resulting coexpression systems bearing both CPR-CYP and RAD54-GFP expression cassettes were designated as CYP3A4/CYP2B6/CYP2D6 + RAD54 systems, respectively and used to detect and evaluate the genotoxic potential of carcinogens and procarcinogens by selective activation and induction of both CPR-CYP and RAD54-GFP expression cassettes in response to DNA damage. Procarcinogens were shown to be predominantly, moderately or not bioactivated by one of the CYP enzymes and thus selectively detected by the specific coexpression system. Aflatoxin B₁ and benzo(a)pyrene were predominantly detected by the CYP3A4 + RAD54 system, while N-nitrosodimethylamine only moderately activated the CYP2B6 + RAD54 reporter system and none of them was identified by the CYP2D6 + RAD54 system. In contrast, the genotoxic carcinogen, methyl methanesulfonate, was detected by all systems.

Our yeast-reporter system can be performed in 384-well microplates to provide efficient genotoxicity testing to identify various carcinogenic compounds and reduce chemical consumption to about 53% as compared with existing 96-well genotoxicity bioassays. In association with a liquid handling robot, this platform enables rapid, cost-effective, and high-throughput screening of numerous analytes in a fully automated and continuous manner without the need for user interaction.

Mycotoxin contamination in laboratory rat feeds and their implications in animal research

Compound feed is particularly vulnerable to multi-mycotoxin contamination. A method for the determination of 12 mycotoxins; enniatins A, A1, B, B1; aflatoxins B1, B2, G1, G2; OTA; ZEA; T-2 and HT-2 by liquid chromatography-tandem mass spectrometry has been developed and applied for the analysis of laboratory rat commercial feeds. The method trueness was checked by recovery assays at three different spiked levels (n = 9). Recoveries ranged from 73% to 112%, and the intra-day and inter-day precision were lower than 9% and 13%, respectively. Limits of quantitation were lower than 15 μg/kg. Twenty-seven laboratory rats feed samples showed multi-contamination by at least three up to six different mycotoxins. ENNs B and B1, followed by ZEA were the most prevalent mycotoxins. T-2, HT-2, and OTA were not detected. ZEA showed the highest concentration levels reaching 492 μg/kg. The results underline the importance of implementing mycotoxin regular surveillance programs for laboratory animal feeds.

In vitro zearalenone adsorption by a mixture of organic and inorganic adsorbents: application of the Box Behnken approach

Zearalenone (ZEA) adsorption by a mixture of organic (yeast cell wall) and inorganic (activated charcoal) adsorbents was evaluated by an incomplete Box Behnken (33) statistical design with a quintuplicate at the central point. The variables analysed were different ratios of adsorbents (yeast cell wall and activated charcoal) at 100:0, 87.5:12.5 and 75:25, pH (3.0, 4.5 and 6.0) and ZEA concentrations (300, 750 and 1,200 ng/ml). The adsorbent mixture at 75:25 showed higher efficiency for ZEA adsorption (≯96.1%) than the 87.5:12.5 ratio (81.3 to 93.7%) and with the pure yeast cell wall (78.1 to 55.7%). The significant variables were the ratio of adsorbent mixture and ZEA concentration. The effect of pH was not significant (P=0.05), indicating that the binding between ZEA and the adsorbent would be stable at different pH (3.0, 4.5 and 6.0). The quadratic model obtained by the Box Behnken (33) design can be used for predictive purposes, because it showed a non-significant deviation (P=49.54%) and a good correlation coefficient (R2=0.98), suggesting that the ZEA adsorption would be maximum (100%) when the adsorbent mixture is set at 75:25 and the ZEA concentration at 300 ng/ml. Although the predictive model showed that an increase in adsorption efficiency could occur in a smaller ZEA concentration (300 ng/ml), the mixture at the 75:25 ratio presented high efficiency (≯98%) in adsorption when high ZEA concentrations were used (1,200 ng/ml), indicating that these mixtures would be able to adsorb a wide range of ZEA concentrations. Therefore, this mixture of yeast cell wall and activated charcoal adsorbents at 75:25 might be a candidate for further in vivo testing.

Mycotoxigenic moulds and mycotoxins in flours consumed in Turkey

BACKGROUND

Aflatoxins (AFs) and ochratoxin A (OTA) are metabolites produced by several fungi of the genera Aspergillus and Penicillium and have been found to contaminate human foods and animal feeds. The aim of this study was to investigate the abundance and diversity of total microfungi and mycotoxigenic fungi in 25 samples of different grain-based flours from four regions of Turkey (Thrace and Central, Northwest and West Anatolia) and to evaluate the level of AF and OTA contamination. Microscopic and polymerase chain reaction analyses were used to identify fungi, while high-performance liquid chromatography was used for the detection of AFs and OTA.

RESULTS

A total of 551 fungal strains were obtained from the samples and identified morphologically and by multi-locus gene sequencing. All samples were contaminated with fungi ((2-4.8) × 10(4) colony-forming units g(-1) ) and three of them exceeded the European Commission (EC) limits. The data also revealed that 70.5 and 14.7% of the fungal isolates were positive for AF and OTA production respectively. In addition, 21 samples were contaminated by AFs (14.98 and 22.4 µg kg(-1) for AFB1 ) and OTA (3.02 and 4.76 µg kg(-1) ) and three of them exceeded the EC limits.

CONCLUSION

This study is the first report on problems with the occurrence of microfungi, mycotoxin contamination, AFs and OTA in different grain-based flour samples from Turkey and highlights developable points of current limits for food and public health safety.

Occurrence of mycotoxins in Polish animal feed in years 2006-2009

We performed a 4-year survey (2006-2009, 1255 samples) of fungal secondary metabolites in feed material (cereal and corn grains) and feedstuffs (silages, mixed feeds). Five major mycotoxin groups were studied, including aflatoxins (AF), ochratoxin A (OTA), trichothecenes [deoxynivalenol (DON), nivalenol (NIV), T-2 toxin, HT-2 toxin], zearalenone (ZEA) and fumonisins (FUM). The metabolites were identified using HPLC methods with fluorescent, UV and MS/MS detection. Both immunoaffinity and SPE columns were used for sample preparation. In eleven samples, the concentration of several mycotoxins exceeded the recommended guidelines for feedstuffs. DON was detected at the highest concentration in the majority of analysed samples (cereal grains, silages and mixed feeds, maximum values ranged from 409 to 14,470 ng/g). Corn grains also contained other Fusarium toxins (FUM) at maximum levels ranging from 435 to 9409 ng/g. The highest average(positive) concentration of the other trichothecenes (NIV, T-2 and HT-2 toxins) was <5.0-139 ng/g. ZEA was found at the highest concentration in corn grains and silages (maximum values ranging from 292 to 603 ng/g and 116 to 1150 ng/g, respectively). The highest average(positive) concentration and the maximum level of OTA were detected in cereal grains (33.0 ng/g in 2009 and 760 ng/g in 2007, respectively). Less than 7% of the 557 samples were contaminated with AF at low levels (maximum of 0.61 ng/g). Our results support the need for further monitoring of mycotoxins in Polish feedstuffs and their components.

Developments in mycotoxin analysis: an update for 2008-2009

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2008 and mid-2009. It covers the major mycotoxins: aflatoxins, alternaria toxins, cyclopiazonic acid, fumonisins, ochratoxin, patulin, trichothecenes and zearalenone. Developments in mycotoxin analysis continue, with emphasis on novel immunological methods and further description of LC-MS and LC-MS/MS, particularly as multimycotoxin applications for different ranges of mycotoxins. Although falling outside the main emphasis of the review, some aspects of natural occurrence have been mentioned, especially if linked to novel method developments.

Developments in mycotoxin analysis: an update for 2007-2008

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2007 and mid-2008. It covers the major mycotoxins: aflatoxins, Alternaria toxins, cyclopiazonic acid, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Some aspects of natural occurrence, particularly if linked to novel aspects of analytical methods, are also included. The review demonstrates the rise of LC-MS methods, the continuing interest in developing alternative and rapid methods and the modification of well-established mycotoxin analytical methods by individual laboratories to meet their own requirements.

Screening of mycotoxins in animal feed from the region of Vojvodina

This paper shows the results of screening of mycotoxins in animal feed originating from the region of Vojvodina. Permanent screening is needed on all levels of production and storage, as well as the use of known methods to reduce mould contamination or toxin content in feedstuffs and feed. A total of 56 representative samples were collected from feed companies from the region of Vojvodina. Samples were collected during February 2009. The collected samples included 41 samples of feedstuffs (soybean, soybean meal, soybean grits, soybean cake, maize, sunflower meal, barley, wheat feed flour, rapeseed meal, dehydrated sugar beet pulps, alfalfa meal, yeast, dried whey, fish meal, meat-bone meal) and 15 samples of complete feedingstuffs. The amounts of aflatoxins, ochratoxin A, zearalenone, fumonisin and deoxynivalenol were determined. Screening method for the analysis was done using Neogen Veratox? testing kits. The test itself is a competitive direct enzyme-linked immunosorbent assay (CD-ELISA). Mycotoxins were present in 71.4% of the samples, but the values determined were below the maximum allowed limits for both Serbian and EC reference values. Zearalenone was found with the highest incidence (57.1% of samples), followed by ochratoxin A (37.5%), fumonisin (33.9%), deoxynivalenol (14.3%) and aflatoxins (3.6%).