Mycotoxins in Maize Silage from China in 2019

Occurrence of regulated, emerging, and masked mycotoxins in Chinese wheat between 2021 and 2022

Wheat is one of three major food crops in China. Wheat grains are prone to contamination with various mycotoxins. The risk of exposure to mycotoxins through the consumption of wheat flour has long been a concern. This study evaluated the occurrence of regulated, marked, and emerging mycotoxins in 304 wheat samples that were randomly sampled from major wheat-producing regions of China. Aflatoxin B1 (AFB1) was detected in only 3 wheat samples, with a maximum concentration of 2.37 μg/kg. Deoxynivalenol (DON) was identified as the most prevalent mycotoxin, being present in 94.4 % of the samples with a maximum concentration of 2.84 mg/kg. Additionally, 11.5 % of the positive DON samples exceeded the maximum Chinese limit of 1000 μg/kg. The incidence of zearalenone (ZEN), zearalanone (ZAN), α-zearalenol, and β-zearalenol in wheat samples were 27.96, 2.96, 2.63, and 2.63 %, respectively. Of 304 wheat samples, 86.2 %, 14.5 and 7.24 % were positive for Deoxynivalenol-3-Glucoside (range: 3.58-609 μg/kg), 3-AcDON (range: 2.31-95.97 μg/kg), and 15-AcDON (range: 2.26-76.65 μg/kg), respectively. Beauvericin (BEA) was detected in 89.14 % of wheat samples with the maximum concentrations 114 μg/kg. However, the average concentration of BEA (2.40 μg/kg) in the positive samples was less than 10 μg/kg. Alternariol (AOH) and moniliformin were detected in 48.68 % and 16.78 % of wheat samples, respectively. Most wheat samples (89 %) were simultaneously contaminated with more than one mycotoxin, with an average of approximately five mycotoxins per sample, and up to 15 mycotoxins were detected in individual samples. In conclusion, DON was the most prevalent mycotoxin in wheat samples, followed by D-3-G, BEA, and AOH, and co-contamination of mycotoxins in wheat samples were very common.

Effects of Mixing Ratio and Lactic Acid Bacteria Preparation on the Quality of Whole-Plant Quinoa and Whole-Plant Corn or Stevia Powder Mixed Silage

Quinoa is the only single plant that can meet all the nutritional needs of human, and its potential for feed utilization has been continuously explored, becoming a prosperous industry for poverty alleviation. In order to further tap the feeding value of whole quinoa, develop quinoa as a feed substitute for conventional crops such as corn, and improve its comprehensive utilization rate, this experiment analyzed the silage quality and mycotoxin content of mixed silage of whole-plant quinoa (WPQ) with whole-plant corn (WPC) or stevia powder(SP) in different proportions, and further improved the silage quality of mixed silage by using two lactic acid bacteria preparations (Sila-Max and Sila-Mix). The quality, microbial population, and mycotoxin levels of quinoa and corn silage, as well as that of the mixed silage of quinoa and stevia, were evaluated using single-factor analysis of variance. The impact of various lactic acid bacteria preparations on the quality of whole-quinoa and whole-corn mixed silage was investigated through two-factor analysis of variance. WPQ and WPC were mixed at the ratio of 5:5 (QB5), 6:4 (QB6), 7:3 (QB7), 8:2 (QB8), 9:1 (QB9) and 10:0 (QB10). SP was mixed with WPQ at the supplemental levels of 0.2% (QB10S2), 0.4% (QB10S4), 0.6% (QB10S6), 0.8% (QB10S8) and 1.0% (QB10S10). After 60 days of silage, the silage indexes, the number of harmful microorganisms, and the mycotoxin levels were measured, to explore the appropriate ratio of mixed silage. The membership function analysis showed that the quality of mixed silage of WPQ with SP was better, and the optimal addition amount of SP was 0.6%. The results of Max and Mix on the quality improvement test of WPQ with WPC mixed silage showed that the two lactic acid bacteria formulations increased CP and AA content, and reduced NH3-N/TN; pH was significantly lower than the control group (p < 0.01), and LA was significantly higher than the control group (p < 0.01). The microbial count results showed that the addition of lactic acid bacteria preparation significantly reduced the number of molds and aerobic bacteria, and the effect of Mix was better than that of Max. When the mixing ratio was between QB7 and QB10, mold was not detected in the lactic-acid-bacteria preparation groups. Max and Mix significantly reduced the levels of mycotoxins, both of which were far below the range of feed safety testing, and 16S rRNA sequencing revealed that the silage microbiota varied with different mixing ratios and whether lactic acid bacteria preparations were used. Max and Mix increased the relative abundance of Firmicutes, with Mix having a more significant effect, especially in the QB6 (65.05%) and QB7 (63.61%) groups. The relative abundance of Lactobacillus was significantly higher than that of the control group (p < 0.05). The relative abundance of Enterobacteriaceae and Streptococcus were negatively and positively correlated with the addition level of quinoa, respectively. Comprehensive analysis showed that adding 0.6% SP to the WPQ and using Mix in mixed silage of WPQ and WPC with the proportion of WPQ no less than 70% had the best silage effect, and was more beneficial to animal health.

Exploring the Efficacy of Using Geotrichum fermentans, Rhodotorula rubra, Kluyveromyce marxiamus, Clay Minerals, and Walnut Nutshells for Mycotoxin Remediation

The aim of this study was to evaluate the effectiveness of nine different biological compounds to reduce mycotoxins concentrations. The hypothesis of this study was that a static in vitro gastrointestinal tract model, as an initial screening tool, can be used to simulate the efficacy of Geotrichum fermentans, Rhodotorula rubra, Kluyveromyce marxiamus yeast cell walls and their polysaccharides, red and white clay minerals, and walnuts nutshells claiming to detoxify AFB1, ZEA, DON, and T-2 toxin mycotoxins. Mycotoxin concentrations were analyzed using high-performance liquid chromatography (HPLC) with fluorescent (FLD) and ultraviolet detectors (UV). The greatest effects on reducing mycotoxin concentrations were determined as follows: for AFB1, inserted G. fermentans cell wall polysaccharides and walnut nutshells; for ZEA, inserted R. rubra and G. fermentans cell walls and red clay minerals; for DON, R. rubra cell wall polysaccharides and red clay minerals; and for T-2 toxin, R. rubra cell walls, K. marxianus, and G. fermentans cell wall polysaccharides and walnut nutshells. The present study indicated that selected mycotoxin-detoxifying biological compounds can be used to decrease mycotoxin concentrations.

Mechanisms by which microbial enzymes degrade four mycotoxins and application in animal production: A review

Mycotoxins are toxic compounds that pose a serious threat to animal health and food safety. Therefore, there is an urgent need for safe and efficient methods of detoxifying mycotoxins. As biotechnology has continued to develop, methods involving biological enzymes have shown great promise. Biological enzymatic methods, which can fundamentally destroy the structures of mycotoxins and produce degradation products whose toxicity is greatly reduced, are generally more specific, efficient, and environmentally friendly. Mycotoxin-degrading enzymes can thus facilitate the safe and effective detoxification of mycotoxins which gives them a huge advantage over other methods. This article summarizes the newly discovered degrading enzymes that can degrade four common mycotoxins (aflatoxins, zearalenone, deoxynivalenol, and ochratoxin A) in the past five years, and reveals the degradation mechanism of degrading enzymes on four mycotoxins, as well as their positive effects on animal production. This review will provide a theoretical basis for the safe treatment of mycotoxins by using biological enzyme technology.

Global distribution, toxicity to humans and animals, biodegradation, and nutritional mitigation of deoxynivalenol: A review

Deoxynivalenol (DON) is one of the main types of B trichothecenes, and it causes health-related issues in humans and animals and imposes considerable challenges to food and feed safety globally each year. This review investigates the global hazards of DON, describes the occurrence of DON in food and feed in different countries, and systematically uncovers the mechanisms of the various toxic effects of DON. For DON pollution, many treatments have been reported on the degradation of DON, and each of the treatments has different degradation efficacies and degrades DON by a distinct mechanism. These treatments include physical, chemical, and biological methods and mitigation strategies. Biodegradation methods include microorganisms, enzymes, and biological antifungal agents, which are of great research significance in food processing because of their high efficiency, low environmental hazards, and drug resistance. And we also reviewed the mechanisms of biodegradation methods of DON, the adsorption and antagonism effects of microorganisms, and the different chemical transformation mechanisms of enzymes. Moreover, nutritional mitigation including common nutrients (amino acids, fatty acids, vitamins, and microelements) and plant extracts was discussed in this review, and the mitigation mechanism of DON toxicity was elaborated from the biochemical point of view. These findings help explore various approaches to achieve the best efficiency and applicability, overcome DON pollution worldwide, ensure the sustainability and safety of food processing, and explore potential therapeutic options with the ability to reduce the deleterious effects of DON in humans and animals.

Detoxifying mycotoxins and antifungal properties of two rumen-derived Enterococcus species in artificially contaminated corn silages

BACKGROUND

Mycotoxins contamination in food and feed has emerged as an issue of serious concern because they pose serious health risks to both humans and livestock. The study aimed to evaluate the effects of two rumen-derived Enterococcus spp. on fermentation and hygienic quality of artificially contaminated corn silages. The toxigenic fungal-infested (FI) and non-fungal infested (NFI) corn was harvested at 1/2 milk line stage and ensiled without additives (CON) or with Enterococcus faecalis (E) or Enterococcus faecium (M).

RESULTS

The pH of FI silages was higher than that of NFI silages, the pH in NFI-M was lower than in NFI-CON. Inoculating E. faecium markedly increased lactic acid concentration compared to CON and E silages. Both E. faecium and E. faecalis decreased the deoxynivalenol (DON) and zearalenone (ZEN) concentrations compared with the CON for FI silages, while E. faecium was more effective in eliminating aflatoxin B₁ (AFB₁ ). The FI silage had higher bacterial and fungal Shannon indexes than NFI silages. The relative abundance (RA) of Aspergillus and Fusarium marked a decline from day 5 to day 90. Inoculating E. faecium and E. faecalis reduced the RA of Penicillium compared to CON. In vitro mycotoxins removal assay indicated that E. faecium was more effective in AFB₁ detoxification while having lower detoxifying ZEN capacity than E. faecalis.

CONCLUSION

Inoculating rumen-derived Enterococcus spp. isolates alleviated the negative effects of fungal infestation on the fermentation and hygienic quality of corn silages by changing the microbial communities and detoxifying mycotoxins. © 2023 Society of Chemical Industry.

Isolation and Characterization of Lactobacillus paracasei 85 and Lactobacillus buchneri 93 to Absorb and Biotransform Zearalenone

As one of the most prevalent estrogenic mycotoxins in cereals and animal feed, zearalenone (ZEN) can cause serious reproductive disorders. ZEN control in food and feed commodities has been an imperative area of research. In this study, 87 lactic acid bacteria (LAB) were isolated from pickles and their ZEN (5 mg/L) removal abilities ranged from 0% to 68.4%. Then, five strains with potent ZEN removal ability (>50%) were identified: Lactobacillus plantarum 22, L. plantarum 37, L. plantarum 47, L. paracasei 85, and L. buchneri 93. Under optimization conditions (48 h, pH 4.0, 37 °C, and 5 mg/L), the highest ZEN removal abilities of L. paracasei 85 and L. buchneri 93 reached 77.7% and 72.8%, respectively. Moreover, the two lactic acid bacteria decreased the toxicity of ZEN, because the levels of β-zearalenol (β-ZOL) transformed from ZEN were more than two-fold higher than α-zearalenol (α-ZOL). Additionally, cell free supernatant and pellet biotransformation of ZEN to α-ZOL and β-ZOL in LAB were detected for the first time. Furthermore, chemical and enzymatical treatments combined with Fourier-transform infrared spectroscopy analysis indicated that exopolysaccharides, proteins, and lipids on the cell wall could bond to ZEN through hydrophobic interactions. Scanning electron microscopy indicated that cell structure damage occurred during the ZEN clearance to L. buchneri 93, but it did not with L. paracasei 85. In addition, various organic acids, alcohols, and esters of the two LAB participated in ZEN removal. Hence, L. paracasei 85 and L. buchneri 93 can be considered as potential detoxification agents for ZEN removal for food and feedstuff.

In Vitro Effects of Enniatin A on Steroidogenesis and Proliferation of Bovine Granulosa Cells

The emerging Fusarium mycotoxins enniatins (ENNs) have been the focus of new research because of their well-documented existence in various cereal and grain products. Research findings indicate that reproductive disorders may be caused by exposure to Fusarium mycotoxins, but little work has evaluated ENNs on reproductive function. Therefore, to determine the effects of ENNA on the proliferation and steroidogenesis of granulosa cells (GC), experiments were conducted using bovine GC cultures. In vitro, ENNA (1−5 μM) inhibited (p < 0.05) hormone-induced GC progesterone and estradiol production. The inhibitory effect of ENNA on estradiol production was more pronounced in small- than large-follicle GC. In large-follicle GC, 0.3 μM ENNA had no effect (p > 0.10) whereas 1 and 3 μM ENNA inhibited GC proliferation. In small-follicle GC, ENNA (1−5 μM) dramatically decreased (p < 0.05) GC proliferation. Using cell number data, the IC50 of ENNA was estimated at 2 μM for both follicle sizes. We conclude that ENNA can directly inhibit ovarian function in cattle, decreasing the proliferation and steroid production of GC.

The control of Fusarium growth and decontamination of produced mycotoxins by lactic acid bacteria

Global crop and food contamination with mycotoxins are one of the primary worldwide concerns, while there are several restrictions regarding approaching conventional physical and chemical mycotoxins decontamination methods due to nutrition loss, sensory attribute reduction in foods, chemical residual, inconvenient operation, high cost of equipment, and high energy consumption of some methods. In this regard, the overarching challenges of mycotoxin contamination in food and food crops require the development of biological decontamination strategies. Using certain lactic acid bacteria (LAB) as generally recognized safe (GRAS) compounds is one of the most effective alternatives due to their potential to release antifungal metabolites against various fungal factors species. This review highlights the potential applications of LAB as biodetoxificant agents and summarizes their decontamination activities against Fusarium growth and Fusarium mycotoxins released into food/feed. Firstly, the occurrence of Fusarium and the instrumental and bioanalytical methods for the analysis of mycotoxins were in-depth discussed. Upgraded knowledge on the biosynthesis pathway of mycotoxins produced by Fusarium offers new insightful ideas clarifying the function of these secondary metabolites. Moreover, the characterization of LAB metabolites and their impact on the decontamination of the mycotoxin from Fusarium, besides the main mechanisms of mycotoxin decontamination, are covered. While the thematic growth inhibition of Fusarium and decontamination of their mycotoxin by LAB is very complex, approaching certain lactic acid bacteria (LAB) is worth deeper investigations.