Efficacy of Bacillus subtilis ANSB060 Biodegradation Product for the Reduction of the Milk Aflatoxin M₁ Content of Dairy Cows Exposed to Aflatoxin B₁

Peppermint essential oil and its nano-emulsion: Potential against aflatoxigenic fungus Aspergillus flavus in food and feed

A facultative parasite called Aspergillus flavus contaminates several important food crops before and after harvest. In addition, the pathogen that causes aspergillosis infections in humans and animals is opportunistic. Aflatoxin, a secondary metabolite produced by Aspergillus flavus, is also carcinogenic and mutagenic, endangering human and animal health and affecting global food security. Peppermint essential oils and plant-derived natural products have recently shown promise in combating A. flavus infestations and aflatoxin contamination. This review discusses the antifungal and anti-aflatoxigenic properties of peppermint essential oils. It then discusses how peppermint essential oils affect the growth of A. flavus and the biosynthesis of aflatoxins. Several cause physical, chemical, or biochemical changes to the cell wall, cell membrane, mitochondria, and associated metabolic enzymes and genes. Finally, the prospects for using peppermint essential oils and natural plant-derived chemicals to develop novel antifungal agents and protect foods are highlighted. In addition to reducing the risk of aspergillosis infection, this review highlights the significant potential of plant-derived natural products and peppermint essential oils to protect food and feed from aflatoxin contamination and A. flavus infestation.

Vibrio gazogenes-dependent disruption of aflatoxin biosynthesis in Aspergillus flavus: the connection with endosomal uptake and hyphal morphogenesis

Aflatoxins, a family of fungal secondary metabolites, are toxic and carcinogenic compounds that pose an enormous threat to global food safety and agricultural sustainability. Specifically agricultural products in African, Southeast Asian and hot and humid regions of American countries suffer most damage from aflatoxin producing molds due to the ideal climate conditions promoting their growth. Our recent studies suggest that Vibrio gazogenes (Vg), an estuarine bacterium non-pathogenic to plants and humans, can significantly inhibit aflatoxin biosynthesis in the producers. In this study, we investigated the mechanism underlying Vg-dependent aflatoxin inhibition using the prominent aflatoxin producer, Aspergillus flavus. We show that aflatoxin inhibition upon Vg treatment was associated with fungal uptake of Vg-prodigiosin, a red pigment, which was consistently visible inside fungal hyphae during treatment. The association of prodigiosin with aflatoxin inhibition was further evident as Serratia marcescens, another prodigiosin producer, significantly inhibited aflatoxin, while non-producers like Escherichia coli, Staphylococcus aureus, Vibrio harveyi, and Vibrio fischeri did not. Also, pure prodigiosin significantly inhibited aflatoxin biosynthesis. Endocytosis inhibitors, filipin and natamycin, reduced the Vg-prodigiosin uptake by the fungus leading to a significant increase in aflatoxin production, suggesting that uptake is endocytosis-dependent. The Vg treatment also reduced hyphal fusion (>98% inhibition) and branching, which are both endosome-dependent processes. Our results, therefore, collectively support our theory that Vg-associated aflatoxin inhibition is mediated by an endocytosis-dependent uptake of Vg-prodigiosin, which possibly leads to a disruption of normal endosomal functions.

Structure Elucidation and Toxicity Analysis of the Byproducts Formed after Biodegradation of Aflatoxins B1 and B2 Using Extracts of Mentha arvensis

The aqueous extracts of leaves and shoots of Mentha arvensis were checked for their potential to biodegrade aflatoxin B1 and B2 (AFB1; 100 µg/L and AFB2; 50 µg/L) through in vitro assays. Overall, the results showed that leaf extract degrades aflatoxins more efficiently than the shoot extract. First, the pH, temperature and incubation time were optimized for maximum degradation by observing this activity at different temperatures between 25 and 60 °C, pH between 2 and 10 and incubation time from 3 to 72 h. In general, an increase in all these parameters significantly increased the percentage of biodegradation. In vitro trials on mature maize stock were performed under optimized conditions, i.e., pH 8, temperature 30 °C and an incubation period of 72 h. The leaf extract resulted in 75% and 80% biodegradation of AFB1 and AFB2, respectively. Whereas the shoot extract degraded both toxins up to 40–48%. The structural elucidation of degraded toxin products by LCMS/MS analysis showed seven degraded products of AFB1 and three of AFB2. MS/MS spectra showed that most of the products were formed by the loss of the methoxy group from the side chain of the benzene ring, the removal of the double bond in the terminal furan ring and the modification of the lactone group, indicating less toxicity compared to the parent compounds. The degraded products showed low toxicity against brine shrimps, confirming that M. arvensis leaf extract has significant potential to biodegrade aflatoxins.

Adsorbents Reduce Aflatoxin M1 Residue in Milk of Healthy Dairy Cow Exposed to Moderate Level Aflatoxin B1 in Diet and Its Exposure Risk for Humans

This study investigated the effect of moderate risk level (8 µg/kg) AFB₁ in diet supplemented with or without adsorbents on lactation performance, serum parameters, milk AFM₁ content of healthy lactating cows and the AFM₁ residue exposure risk in different human age groups. Forty late healthy lactating Holstein cows (270 ± 22 d in milk; daily milk yield 21 ± 3.1 kg/d) were randomly assigned to four treatments: control diet without AFB₁ and adsorbents (CON), CON with 8 μg/kg AFB₁ (dry matter basis, AF), AF + 15 g/d adsorbent 1 (AD1), AF + 15 g/d adsorbent 2 (AD2). The experiment lasted for 19 days, including an AFB₁-challenge phase (day 1 to 14) and an AFB₁-withdraw phase (day 15 to 19). Results showed that both AFB₁ and adsorbents treatments had no significant effects on the DMI, milk yield, 3.5% FCM yield, milk components and serum parameters. Compared with the AF, AD1 and AD2 had significantly lower milk AFM₁ concentrations (93 ng/L vs. 46 ng/L vs. 51 ng/L) and transfer rates of dietary AFB₁ into milk AFM₁ (1.16% vs. 0.57% vs. 0.63%) (p < 0.05). Children aged 2–4 years old had the highest exposure risk to AFM₁ in milk in AF, with an EDI of 1.02 ng/kg bw/day and a HI of 5.11 (HI > 1 indicates a potential risk for liver cancer). Both AD1 and AD2 had obviously reductions in EDI and HI for all population groups, whereas, the EDI (≥0.25 ng/kg bw/day) and HI (≥1.23) of children aged 2–11 years old were still higher than the suggested tolerable daily intake (TDI) of 0.20 ng/kg bw/day and 1.00 (HI). In conclusion, moderate risk level AFB₁ in the diet of healthy lactating cows could cause a public health hazard and adding adsorbents in the dairy diet is an effective measure to remit AFM₁ residue in milk and its exposure risk for humans.

Novel strategies for degradation of aflatoxins in food and feed: A review

Aflatoxins are toxic secondary metabolites mainly produced by Aspergillus fungi, posing high carcinogenic potency in humans and animals. Dietary exposure to aflatoxins is a global problem in both developed and developing countries especially where there is poor regulation of their levels in food and feed. Thus, academics have been striving over the decades to develop effective strategies for degrading aflatoxins in food and feed. These strategies are technologically diverse and based on physical, chemical, or biological principles. This review summarizes the recent progress on novel aflatoxin degradation strategies including irradiation, cold plasma, ozone, electrolyzed oxidizing water, organic acids, natural plant extracts, microorganisms and enzymes. A clear understanding of the detoxification efficiency, mechanism of action, degradation products, application potential and current limitations of these methods is presented. In addition, the development and future perspective of nanozymes in aflatoxins degradation are introduced.

Enhancing the Utilization of Palm Leaf Hay Using Bacillus subtilis and Phanerochaete chrysosporium in the Diet of Lambs Under Desert Conditions

The efficiency of the bacterium Bacillus subtilis and white-rot fungus Phanerochaete chrysosporium on growth performance, blood metabolites, carcass characteristics, meat composition and nutrient digestibility of lambs fed crushed whole palm leaf hay was investigated for 105 d. In Experiment 1 (Growth experiment), twenty-four lambs (29.5 ± 1.25 kg) were divided into four feed-based treatments: (1) concentrate and wheat straw ad libitum (control), (2) palm leaf hay (DPL), (3) palm leaf hay supplemented with 2 g of B. subtilis and P. chrysosporium (DPL2) or (4) palm leaf hay supplemented with 4 g of B. subtilis and P. chrysosporium (DPL4). In Experiment 2 (Digestibility experiment), twelve rams, three from each treatment, were used to study nutrient digestibility using the faecal bag technique. Results of the Experiment 1 showed that the DPL4 showed greater (P=0.049) live-weight gain than the control. The diets containing palm leaf hay showed lower (P=0.001) roughage and total feed intake and higher (P=0.001) feed efficiency than the control. Increased serum total protein, globulin, urea-N, aspartate aminotransferase and alanine aminotransferase (ALT) levels were observed with the DPL4 (P˂0.05). Additionally, diets containing palm leaf hay showed higher ALT levels than the control. The DPL4 increased the hot carcass weight (P=0.006) and dressing percentage (P=0.036), and the diets supplemented with B. subtilis and P. chrysosporium decreased (P˂0.05) the tail fat and all fat levels compared with the DPL treatment. Results of the Experiment 2 showed that nutrient digestibility was lower (P˂0.05) with the DPL and DPL2 than with the control and DPL4. Compared with the control, nutrient digestibility of DPL4 was not affected. It is concluded that replacement of wheat straw with palm leaf hay did not affect the feed utilization or animal performance of the lambs; however, supplementation with B. subtilis and P. chrysosporium at 4 g/lamb daily enhanced the growth performance, and carcass characteristics without any adverse effects on blood metabolites.

Mycotoxin toxicity and residue in animal products: Prevalence, consumer exposure and reduction strategies - A review

Mycotoxin residues are transferred from feed to animal products, yet, less attention has been paid to it in developing countries. There is a need to find alternative alleviation material for reducing the impact of mycotoxin. This review is meant to elucidate different additives that can reduce mycotoxin residue in animal products in the world, especially in developing countries. There is evidence of relationship between mycotoxin residue in breast milk of nursing mothers and mycotoxin exposure through crop and animal product (egg and milk) intake, especially in Asia, Africa, Middle East, Latin America, and some parts of Europe. Younger livestock tends to have more toxin residues in their tissue compared to older ones. Grazing animal are also exposed to mycotoxin intake which corresponds to high level of mycotoxins in their products including meat and milk. This review shows that phytogenic, probiotic, and prebiotic additives can decrease mycotoxin residues in milk, eggs, meat liver and other tissues of livestock. Specifically, bentonites, difructose anhydride III, yeast (Trichosporon mycotoxinivorans), Bacillus spp., or their biodegradable products can reduce mycotoxin residue in animal products. In addition, Ally isothiocyanates from mustard seed were able to mitigate mycotoxins in silo-simulated system. Evidence shows that there are now low-cost, accessible, and eco-friendly additives, which could alleviate the effect of mycotoxin in feed and food. In addition, there is need for aggressive public awareness and farmers' education on the prevalence, and danger caused by mycotoxins, as well as detoxification strategies that can reduce toxin absorption into animal products.