Aflatoxin B1 and ochratoxin A reduction by Lactobacillus spp. during bread making

BACKGROUND

Aflatoxin B1 (AFB1) and ochratoxin A (OTA) are among the most important mycotoxins with common presence in bread and bakery products. Biological detoxification of mould food spoilage and mycotoxin contamination by lactic acid bacteria (LABs) exhibits high potential on a cost-effective and large scale. In this work, the effect of Lactobacillus strains isolated from goat milk whey on reducing AFB1 and OTA during bread making was evaluated by the determination of mycotoxin reduction potential of 12 LAB strains after 72 h incubation in De Man-Rogosa-Sharpe (MRS) broth (37 °C). The most effective LABs were lyophilized and added as ingredient in bread formulation, analysing mycotoxins by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry after bread fermentation and baking.

RESULTS

AFB1 was reduced in MRS broth by seven LABs (11-35%), highlighting Lactobacillus plantarum B3 activity; while all LABs reduced OTA (12-40%) with L. plantarum B3 and Lactobacillus paracasei B10 as the most active strains. Both LABs were lyophilized and added in contaminated bread with and without yeast, reaching AFB1 and OTA reductions up to 27% and 32% respectively in dough and up to 55% and 34% respectively in bread.

CONCLUSION

The selected strains significantly reduced AFB1 and OTA during bread fermentation, pointing to a potential biocontrol strategy for mycotoxins detoxification in bread and bakery products. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Assessment of aflatoxin exposure, growth faltering and the gut microbiome among children in rural Guatemala: protocol for an observational prospective cohort and bioreactor simulations

INTRODUCTION

Aflatoxin B1 (AFB1) is a carcinogen produced by Aspergillus flavus and Aspergillus parasiticus which grow on maize. Given the high prevalence of child stunting (ie, impaired growth) and other nutritional disorders in low-income and middle-income countries, where maize is consumed, the role of aflatoxin exposure may be significant. Observational reports have demonstrated associations between aflatoxin exposure and impaired child growth; however, most have been cross-sectional and have not assessed seasonal variations in aflatoxin, food preparation and dynamic changes in growth. Biological mechanistic data on how aflatoxin may exert an impact on child growth is missing. This study incorporates a prospective cohort of children from rural Guatemala to assess (1) temporal associations between aflatoxin exposure and child growth and (2) possible mediation of the gut microbiome among aflatoxin exposure, inflammation and child growth.

METHODS AND ANALYSIS

We will prospectively evaluate aflatoxin exposure and height-for-age difference trajectories for 18 months in a cohort of 185 children aged 6-9 months at enrolment. We will assess aflatoxin exposure levels and biomarkers of gut and systemic inflammation. We will examine the faecal microbiome of each child and identify key species and metabolic pathways for differing AFB1 exposure levels and child growth trajectories. In parallel, we will use bioreactors, inoculated with faeces, to investigate the response of the gut microbiome to varying levels of AFB1 exposure. We will monitor key microbial metabolites and AFB1 biotransformation products to study nutrient metabolism and the impact of the gut microbiome on aflatoxin detoxification/metabolism. Finally, we will use path analysis to summarise the effect of aflatoxin exposure and the gut microbiome on child growth.

ETHICS AND DISSEMINATION

Ethics approval was obtained from Arizona State University Institutional Review Board (IRB; STUDY00016799) and Wuqu' Kawoq/Maya Health Alliance IRB (WK-2022-003). Findings will be disseminated in scientific presentations and peer-reviewed publications.

Antagonism of Cyanamide-3-O-glucoside and protocatechuic acid on Aflatoxin B1-induced toxicity in zebrafish larva (Danio rerio)

The zebrafish model was used to evaluate the antioxidant properties of cyanidin-3-O-glucoside (C₃G) and its metabolite protocatechuic acid (PCA) against aflatoxin B₁ (AFB₁)-induced hepatotoxicity and oxidative stress. In this study, zebrafish larvae were cultured for 3 days post fertilization (dpf) and then induced with AFB₁. After induced 4 h, 8 h, 12 h, and 24 h, 5 μg/mL C₃G/PCA was added and then co-cultured to 5 dpf, respectively. The experiments showed that C₃G/PCA suppressed AFB₁-induced zebrafish liver atrophy and delayed the absorption of the yolk sac. In addition, reactive oxygen species (ROS) and cell death were also significantly decreased by 5 μg/mL C₃G/PCA (P ˂ 0.05). C₃G/PCA significantly reduced hepatic biomarkers in the serum contents (P ˂ 0.05). Besides, glutathione (GSH) contents were significantly upregulated, and the activities of superoxide dismutase (SOD) and catalase (CAT) were significantly elevated in zebrafish (P ˂ 0.05). The addition of 5 μg/mL C₃G/PCA was capable of reducing the apoptotic levels of caspase-9 and caspase-3 after 100 ng/mL AFB₁ intoxication. In conclusion, these results suggested that C₃G and its metabolite PCA might antagonize the hepatotoxicity of AFB₁, reduce oxidative damage and inhibit cell death.

Biodetoxification and Protective Properties of Probiotics

Probiotic consumption is recognized as being generally safe and correlates with multiple and valuable health benefits. However, the mechanism by which it helps detoxify the body and its anti-carcinogenic and antimutagenic potential is less discussed. A widely known fact is that globalization and mass food production/cultivation make it impossible to keep all possible risks under control. Scientists associate the multitude of diseases in the days when we live with these risks that threaten the population’s safety in terms of food. This review aims to explore whether the use of probiotics may be a safe, economically viable, and versatile tool in biodetoxification despite the numerous risks associated with food and the limited possibility to evaluate the contaminants. Based on scientific data, this paper focuses on the aspects mentioned above and demonstrates the probiotics’ possible risks, as well as their anti-carcinogenic and antimutagenic potential. After reviewing the probiotic capacity to react with pathogens, fungi infection, mycotoxins, acrylamide toxicity, benzopyrene, and heavy metals, we can conclude that the specific probiotic strain and probiotic combinations bring significant health outcomes. Furthermore, the biodetoxification maximization process can be performed using probiotic-bioactive compound association.

Detoxification approaches of mycotoxins: by microorganisms, biofilms and enzymes

Mycotoxins are generally found in food, feed, dairy products, and beverages, subsequently presenting serious human and animal health problems. Not surprisingly, mycotoxin contamination has been a worldwide concern for many research studies. In this regard, many biological, chemical, and physical approaches were investigated to reduce and/or remove contamination from food and feed products. Biological detoxification processes seem to be the most promising approaches for mycotoxins removal from food. The current review details the newest progress in biological detoxification (adsorption and metabolization) through microorganisms, their biofilms, and enzymatic degradation, finally describing the detoxification mechanism of many mycotoxins by some microorganisms. This review also reports the possible usage of microorganisms as mycotoxins’ binders in various food commodities, which may help produce mycotoxins-free food and feed.

Probiotic and Antifungal Attributes of Levilactobacillus brevis MYSN105, Isolated From an Indian Traditional Fermented Food Pozha

The use of probiotics and antifungal capabilities of the lactic acid bacteria (LAB) isolated from different niches is a strategy to prepare functional cultures and biopreservatives for food/feed industries. In the present study, LAB strains isolated from an Indian traditional fermented food, Pozha, were evaluated for their probiotic properties and biocontrol potential. A total of 20 LAB isolates were selected from Pozha samples collected aseptically and screened for their antagonistic activity against Fusarium verticillioides. Among the bioactive isolates, Lacticaseibacillus brevis MYSN105 showed the highest antifungal activity in vitro, causing some morphological alterations such as damaged mycelia and deformed conidia. Cell-free supernatant (CFS) from L. brevis MYSN105 at 16% concentration effectively reduced the mycelial biomass to 0.369 g compared to 1.938 g in control. Likewise, the conidial germination was inhibited to 20.12%, and the seed treatment using CFS induced a reduction of spore count to 4.1 × 10⁶ spores/ml compared to 1.1 × 10⁹ spores/ml for untreated seeds. The internal transcribed spacer (ITS) copy number of F. verticillioides decreased to 5.73 × 10⁷ and 9.026 × 10⁷ by L. brevis MYSN105 and CFS treatment, respectively, compared to 8.94 × 10¹⁰ in control. The L. brevis MYSN105 showed high tolerance to in vitro gastrointestinal conditions and exhibited high adhesive abilities to intestinal epithelial cell lines. The comparative genome analysis demonstrated specific secondary metabolite region coding for bacteriocin and T3PKS (type III polyketide synthase) possibly related to survival and antimicrobial activity in the gut environment. Our results suggest that L. brevis MYSN105 has promising probiotic features and could be potentially used for developing biological control formulations to minimize F. verticillioides contamination and improve food safety measures.

Biological Control and Mitigation of Aflatoxin Contamination in Commodities

Aflatoxins (AFs) are toxic secondary metabolites produced mostly by Aspergillus species. AF contamination entering the feed and food chain has been a crucial long-term issue for veterinarians, medicals, agroindustry experts, and researchers working in this field. Although different (physical, chemical, and biological) technologies have been developed, tested, and employed to mitigate the detrimental effects of mycotoxins, including AFs, universal methods are still not available to reduce AF levels in feed and food in the last decades. Possible biological control by bacteria, yeasts, and fungi, their excretes, the role of the ruminal degradation, pre-harvest biocontrol by competitive exclusion or biofungicides, and post-harvest technologies and practices based on biological agents currently used to alleviate the toxic effects of AFs are collected in this review. Pre-harvest biocontrol technologies can give us the greatest opportunity to reduce AF production on the spot. Together with post-harvest applications of bacteria or fungal cultures, these technologies can help us strictly reduce AF contamination without synthetic chemicals.

Efficacy of Potentially Probiotic Fruit-Derived Lactobacillus fermentum, L. paracasei and L. plantarum to Remove Aflatoxin M1 In Vitro

This study evaluated the efficacy of potentially probiotic fruit-derived Lactobacillus isolates, namely, L. paracasei 108, L. plantarum 49, and L. fermentum 111, to remove aflatoxin M₁ (AFM₁) from a phosphate buffer solution (PBS; spiked with 0.15 µg/mL AFM₁). The efficacy of examined isolates (approximately 10⁹ cfu/mL) as viable and non-viable cells (heat-killed; 100 °C, 1 h) to remove AFM₁ was measured after 1 and 24 h at 37 °C. The recovery of AFM₁ bound to bacterial cells after washing with PBS was also evaluated. Levels of AFM₁ in PBS were measured with high-performance liquid chromatography. Viable and non-viable cells of all examined isolates were capable of removing AFM₁ in PBS with removal percentage values in the range of 73.9–80.0% and 72.9–78.7%, respectively. Viable and non-viable cells of all examined Lactobacillus isolates had similar abilities to remove AFM₁. Only L. paracasei 108 showed higher values of AFM₁ removal after 24 h for both viable and non-viable cells. Percentage values of recovered AFM₁ from viable and non-viable cells after washing were in the range of 13.4–60.6% and 10.9–47.9%, respectively. L. plantarum 49 showed the highest AFM₁ retention capacity after washing. L. paracasei 108, L. plantarum 49, and L. fermentum 111 could have potential application to reduce AFM₁ to safe levels in foods and feeds. The cell viability of examined isolates was not a pre-requisite for their capacity to remove and retain AFM₁.

Lactic acid bacteria with promising AFB1 binding properties as an alternative strategy to mitigate contamination on brewers' grains

Adsorption of molecules to the cell walls of microorganisms plays an important role in helping to prevent animal exposure to the toxic and carcinogenic effects of aflatoxins (AFs). The aim of this study was to evaluate the ability of LAB strains, isolated from brewers' grains, to adsorb aflatoxin B₁ (AFB₁). All LAB were able to reduce the bioavailability of AFB₁ from phosphate buffered-saline (PBS). In addition, the strains retained their effectiveness even after heat treatment. The AFB₁-LAB complex stability was first evaluated through sequential washing steps. These assays demonstrated that a low percentage of AFB₁ was released after consecutive washes. After subjecting the complex to different pH and bile salt treatments, the percentage of bound AF decreased, as compared to the control, but remained at high levels. Finally, to simulate the formation of the AFB₁-LAB complex at conditions similar to those of the gastrointestinal tract, LAB and AFB₁ were homogenized in PBS adjusted at acidic conditions or under different bile salt concentrations. In general, LAB strains showed the highest AFB₁ adsorption at the lowest pH (2) and bile salt concentration (0.05%). In conclusion, the studied strains represent promising biocontrol agents for preventing and/or ameliorating the AFB₁ contamination of feed.

Characteristics, Occurrence, Detection and Detoxification of Aflatoxins in Foods and Feeds

Mycotoxin contamination continues to be a food safety concern globally, with the most toxic being aflatoxins. On-farm aflatoxins, during food transit or storage, directly or indirectly result in the contamination of foods, which affects the liver, immune system and reproduction after infiltration into human beings and animals. There are numerous reports on aflatoxins focusing on achieving appropriate methods for quantification, precise detection and control in order to ensure consumer safety. In 2012, the International Agency for Research on Cancer (IARC) classified aflatoxins B1, B2, G1, G2, M1 and M2 as group 1 carcinogenic substances, which are a global human health concern. Consequently, this review article addresses aflatoxin chemical properties and biosynthetic processes; aflatoxin contamination in foods and feeds; health effects in human beings and animals due to aflatoxin exposure, as well as aflatoxin detection and detoxification methods.

Aflatoxins: Producing-Molds, Structure, Health Issues and Incidence in Southeast Asian and Sub-Saharan African Countries

This review aims to update the main aspects of aflatoxin production, occurrence and incidence in selected countries, and associated aflatoxicosis outbreaks. Means to reduce aflatoxin incidence in crops were also presented, with an emphasis on the environmentally-friendly technology using atoxigenic strains of Aspergillus flavus. Aflatoxins are unavoidable widespread natural contaminants of foods and feeds with serious impacts on health, agricultural and livestock productivity, and food safety. They are secondary metabolites produced by Aspergillus species distributed on three main sections of the genus (section Flavi, section Ochraceorosei, and section Nidulantes). Poor economic status of a country exacerbates the risk and the extent of crop contamination due to faulty storage conditions that are usually suitable for mold growth and mycotoxin production: temperature of 22 to 29 °C and water activity of 0.90 to 0.99. This situation paralleled the prevalence of high liver cancer and the occasional acute aflatoxicosis episodes that have been associated with these regions. Risk assessment studies revealed that Southeast Asian (SEA) and Sub-Saharan African (SSA) countries remain at high risk and that, apart from the regulatory standards revision to be more restrictive, other actions to prevent or decontaminate crops are to be taken for adequate public health protection. Indeed, a review of publications on the incidence of aflatoxins in selected foods and feeds from countries whose crops are classically known for their highest contamination with aflatoxins, reveals that despite the intensive efforts made to reduce such an incidence, there has been no clear tendency, with the possible exception of South Africa, towards sustained improvements. Nonetheless, a global risk assessment of the new situation regarding crop contamination with aflatoxins by international organizations with the required expertise is suggested to appraise where we stand presently.

Recombinant Aflatoxin-Degrading F420H2-Dependent Reductase from Mycobacterium smegmatis Protects Mammalian Cells from Aflatoxin Toxicity

Aflatoxins are carcinogenic secondary metabolites of fungi that contaminate many staple crops and foods. Aflatoxin contamination is a worldwide problem, especially in developing countries, posing health hazards, e.g., causing aflatoxicosis and hepatocellular carcinoma, and even death. Biological solutions for aflatoxin detoxification are environmentally friendly and a cheaper alternative than chemical methods. The aims of the current study were to investigate: (1) the ability of MSMEG_5998, an aflatoxin-degrading F₄₂₀H₂-dependent reductase from Mycobacterium smegmatis, to degrade aflatoxin B1 (AFB1) and reduce AFB1-caused damage in HepG2 cell culture model; and (2) whether a thioredoxin (Trx) linkage of MSMEG_5998 enhanced the enzyme activity. We show that Trx-linked MSMEG_5998 degraded 63% AFB1 and native MSMEG_5998 degraded 31% after 4 h at 22 °C, indicating that the Trx-linked enzyme had a better AFB1-degrading ability. In a HepG2 cell culture model, Trx-linked MSMEG_5998 reduced DNA damage and p53-mediated apoptosis caused by AFB1 to a greater extent than the native enzyme. These findings suggest that Trx-linked MSMEG_5998 could potentially be developed to protect the liver from AFB1 damage, or as a candidate protein to reduce AFB1-related toxicity in animals.

Mycotoxin patulin in food matrices: occurrence and its biological degradation strategies

Patulin is a mycotoxin produced by a number of filamentous fungal species. It is a polyketide secondary metabolite which can gravely cause human health problems and food safety issues. This review deals with the occurrence of patulin in major food commodities from 2008 to date, including historical aspects, source, occurrence, regulatory limits and its toxicity. Most importantly, an overview of the recent research progress about the biodegradation strategies for contaminated food matrices is provided. The physical and chemical approaches have some drawbacks such as safety issues, possible losses in the nutritional quality, chemical hazards, limited efficacy, and high cost. The biological decontamination based on elimination or degradation of patulin using yeast, bacteria, and fungi has shown good results and it seems to be attractive since it works under mild and environment-friendly conditions. Further studies are needed to make clear the detoxification pathways by available potential biosorbents and to determine the practical applications of these methods at a commercial level to remove patulin from food products with special reference to their effects on sensory characteristics of foods.

Lactobacillus rhamnosus GG modulates gastrointestinal absorption, excretion patterns, and toxicity in Holstein calves fed a single dose of aflatoxin B1

The aim of the present study was to evaluate the effects of Lactobacillus rhamnosus GG (LGG; ATCC 53013) on growth performance and hepatotoxicity in calves fed a single dose of aflatoxin B₁ (AFB₁) and to investigate the absorption, distribution, and elimination of AFB₁ and the hydroxylated metabolite aflatoxin M₁ (AFM₁) in rumen fluid, blood, and excretions. Twenty-four male Holstein calves were blocked for body weight and age and were randomly assigned to 1 of 3 treatment groups: (1) untreated control, (2) treated with 4.80 mg of AFB₁ (AFB₁ only), or (3) treated with 1 × 10¹⁰ cfu of LGG suspension and 4.80 mg of AFB₁ (AFB₁ plus LGG). The calves received LGG suspension in 50 mL of phosphate-buffered saline daily via oral administration for 14 d before and on the day they received a single oral dose of AFB₁. Body weight was recorded at the beginning of the study (before LGG administration), at the day of AFB₁ administration, and at the end of the trial. Rumen fluid, blood, urine, and feces samples were collected continuously for 96 h after AFB₁ administration. Average daily gain (ADG) and plasma biochemical parameters were analyzed, and concentrations of AFB₁ and AFM₁ in the samples were determined for monitoring excretion pattern and toxicokinetics. The results showed that ADG was lower in AFB₁-treated animals; LGG administration partially mitigated the decrease in ADG (0.85 ± 0.08 vs. 0.76 ± 0.18 kg of gain/d). The AFB₁ treatment increased plasma aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase levels. Administration of LGG alleviated the AFB₁-induced increase in plasma enzymes activity. The excretion patterns of AFB₁ and AFM₁ were surprisingly regular; toxins were rapidly detected in all samples after a single oral dose of AFB₁, and the peak of toxins concentrations was sequentially reached in rumen fluid, plasma, urine, and feces (except AFM₁ in rumen fluid), followed by an exponential decrease. The excretion curves showed that AFB₁ and AFM₁ concentrations were the highest in feces and urine, respectively. Administration of LGG decreased the concentrations of free AFB₁ and AFM₁ in rumen fluid and reduced the release of toxins into plasma and urine. Toxicokinetic parameters (except for the time of maximum concentration and the terminal half-life) were reduced by LGG administration. In conclusion, the absorption, distribution, and excretion of AFB₁ and AFM₁ were rapid in calves fed a single dose of AFB₁. Urine was the main route for the excretion of AFM₁, and the clearance pattern from the peak of concentration was well fitted by exponential decreasing function. Administration of LGG reduced the absorption of AFB₁ in the gastrointestinal tract by increasing the excretion via the feces, thus alleviating the hepatotoxic effect of AFB₁.

Contaminants in Grain-A Major Risk for Whole Grain Safety?

Grains are the main energy and carbohydrate sources for human nutrition globally. Governmental and non-governmental authorities recommend whole grains as a healthy food choice. The role of contaminants in (whole) grains and how to mitigate any potential risk following their consumption has not been reported. With this narrative review, we shed light on the potential human health risk from contaminants in whole grains and elaborate strategies to mitigate such risk. We found that grains represent a significant source of food-borne contaminants, the main ones being; mycotoxins including (A) aflatoxin B1; (B) ochratoxin A; (C) fumonisin B1; (D) deoxynivalenol; (E) zearalenone; toxic metals like arsenic, cadmium and lead; as well as process contaminants such as acrylamide. Whole grains usually contain more contaminants than refined products. However, whole grains also provide more nutrients that may reduce the impact of these contaminants. Strict regulatory thresholds aim to minimize the risk of contaminants to public health. The consumer can further impact on the mitigation of any risk by eating a healthy diet filled with nutrient-dense foods such as whole grains and probiotics. The risk posed by contaminants from whole grains do not outweigh the known nutritional benefits of whole grain consumption.

Biological Degradation of Aflatoxin B₁ by Cell-Free Extracts of Bacillus velezensis DY3108 with Broad PH Stability and Excellent Thermostability

(1) Background: Aflatoxin contamination in food and grain poses serious problems both for economic development and public health protection, thus leading to a focus on an effective approach to control it; (2) Methods: Aflatoxin B₁ (AFB₁) degrading bacteria were isolated using a medium containing coumarin as the sole carbon source, and the biodegradation of AFB₁ by the isolate was examined by high performance liquid chromatography, and liquid chromatography mass spectrometry; (3) Results: a bacterial strain exhibiting strong AFB1 degradation activity (91.5%) was isolated and identified as Bacillusvelezensis DY3108. The AFB₁ degrading activity was predominantly attributed to the cell-free supernatant of strain DY3108. Besides, it was heat-stable and resistant to proteinase K treatment but sensitive to sodium dodecyl sulfate treatment. The optimal temperature for the maximal degradation of AFB₁ was 80 °C. Even more notable, the supernatant showed a high level of activity over a broad pH (4.0 to 11.0) and exhibited the highest degradation (94.70%) at pH 8.0. Cytotoxicity assays indicated that the degradation products displayed significantly (p < 0.05) lower cytotoxic effects than the parent AFB₁; (4) Conclusions: B.velezensis DY3108 might be a promising candidate for exploitation in AFB₁ detoxification and bioremediation in food and feed matrices.

Aflatoxin in foodstuffs: Occurrence and recent advances in decontamination

Aflatoxins are highly toxic compounds produced as secondary metabolites by some Aspergillus species, whose occurrence have been reported predominantly in several types of foods of low moisture content, while aflatoxin biotransformation products have been reported mainly in milk and milk products. This review deals with the occurrence of aflatoxins in some of the major food products in the last 5 years including regulatory aspects, and recent advances in detoxification strategies for contaminated foods. Aflatoxin contamination in cereals including corn and peanut is still a public health problem for some populations, especially in African countries. Despite that most of physical and chemical methods for aflatoxin detoxification may affect the nutritional properties of food, or are not safe for human consumption, gamma-radiation and ozone applications have demonstrated great potential for detoxification of aflatoxins in some food matrices. Biological methods based on removal or degradation of aflatoxins by bacterial and yeast have good perspectives, although further studies are needed to clarify the detoxification mechanisms by microorganisms and determine practical aspects of the use of these methods in food products, especially their potential effects on sensory characteristics of foods.

Effects of lactic acid bacteria and smectite after aflatoxin B1 challenge on the growth performance, nutrient digestibility and blood parameters of broilers

This study aimed to investigate the effect of lactic acid bacteria (LAB) and smectite on the growth performance, nutrient digestibility and blood parameters of broilers that were fed diets contaminated with aflatoxin B₁ (AFB₁ ). A total of 480 newly hatched male Arbor Acres broilers were randomly allocated into four groups with six replicates of 20 chicks each. The broilers were fed diets with the AFB₁ (40 μg/kg) challenge or without (control) it and supplemented with smectite (3.0 g/kg) or LAB (4.0 × 10¹⁰  CFU/kg) based on the AFB₁ diet. The trial lasted for 42 days. The results showed that during days 1-42 of AFB₁ challenge, the feed intake (FI) and body weight gain (BWG) were depressed (p < .05). The inclusion of LAB and smectite increased (p < .05) the BWG by 71.58 and 41.89 g/bird, respectively, which reached the level of the control diet (p ≥ .05), but there were no differences (p ≥ .05) in performance between LAB and smectite. LAB and smectite also increased (p < .05) the apparent total tract digestibility of the crude protein. Regarding the blood parameters, AFB₁ decreased (p < .05) the levels of red blood cell count, haematocrit, mean corpuscular volume, haemoglobin, albumin and total protein. In the meantime, the AFB₁ increased (p < .05) leucocyte counts, urea nitrogen, cholesterol, total bilirubin, creatinine, glutamic-pyruvic transaminase, glutamic oxaloacetic transaminase and alkaline phosphatase. By contrast, LAB and smectite affected (p < .05) these parameters in the opposite direction. It can be concluded that after the AFB₁ challenge, LAB and smectite have similar effects on the growth and health of the broilers, suggesting that LAB could be an alternative against AFB₁ in commercial animal feeds.

Degradation of aflatoxin B1 from naturally contaminated maize using the edible fungus Pleurotus ostreatus

Aflatoxins are highly carcinogenic secondary metabolites that can contaminate approximately 25% of crops and that cause or exacerbate multiple adverse health conditions, especially in Sub-Saharan Africa and South and Southeast Asia. Regulation and decontamination of aflatoxins in high exposure areas is lacking. Biological detoxification methods are promising because they are assumed to be cheaper and more environmentally friendly compared to chemical alternatives. White-rot fungi produce non-specific enzymes that are known to degrade aflatoxin in in situ and ex situ experiments. The aims of this study were to (1) decontaminate aflatoxin B₁ (AFB₁) in naturally contaminated maize with the edible, white-rot fungus Pleurotus ostreatus (oyster mushroom) using a solid-state fermentation system that followed standard cultivation techniques, and to (2) and to assess the risk of mutagenicity in the resulting breakdown products and mushrooms. Vegetative growth and yield characteristics of P. ostreatus were not inhibited by the presence of AFB₁. AFB₁ was degraded by up to 94% by the Blue strain. No aflatoxin could be detected in P. ostreatus mushrooms produced from AFB₁-contaminated maize. Moreover, the mutagenicity of breakdown products from the maize substrate, and reversion of breakdown products to the parent compound, were minimal. These results suggest that P. ostreatus significantly degrades AFB₁ in naturally contaminated maize under standard cultivation techniques to levels that are acceptable for some livestock fodder, and that using P. ostreatus to bioconvert crops into mushrooms can reduce AFB₁-related losses.