Effect of Acclimatization in Elevated CO2 on Growth and Aflatoxin B1 Production by Aspergillus flavus Strains on Pistachio Nuts

There is little knowledge of the effect of acclimatization of Aspergillus flavus strains to climate-related abiotic factors and the subsequent effects on growth and aflatoxin B1 (AFB1) production. In this study, two strains of A. flavus (AB3, AB10) were acclimatized for five generations in elevated CO2 (1000 ppm × 37 °C) on a milled pistachio-based medium. A comparison was made of the effects of non-acclimatized strains and those that were acclimatized when colonizing layers of pistachio nuts exposed to 35 or 37 °C, 400 or 1000 ppm CO2, and 0.93 or 0.98 water activity (aw), respectively. Acclimatization influenced the fitness in terms of the growth of one strain, while there was no significant effect on the other strain when colonizing pistachio nuts. AFB1, production was significantly stimulated after ten days colonization when comparing the non-acclimatized and the acclimatized AB3 strain. However, there was no significant increase when comparing these for strain AB10. This suggests that there may be inter-strain differences in the effects of acclimatization and this could have a differential influence on the mycotoxin contamination of such commodities.

Effect of Aviation Spray Adjuvant on Improving Control of Fusarium Head Blight and Reducing Mycotoxin Contamination in Wheat

Fusarium head blight (FHB) and its mycotoxin contamination are among the main factors affecting wheat yield and quality. There is an urgent need to develop an efficient strategy to prevent and control the FHB disease and reduce the mycotoxin level in the wheat product. As a triazolinthione fungicide, prothioconazole is an effective broad-spectrum fungicide to control various diseases of wheat by foliar spraying. However, prothioconazole has potential harm to the female reproductive system, and its metabolism prothioconazole-desthio has teratogenicity. Considering this point, the plant protection unmanned aerial vehicles (UAVs) are undoubtedly a suitable choice for the field application of prothioconazole. In this work, by spraying 30% prothioconazole dispersible oil suspensions, we report that aviation spray adjuvant of methylated vegetable oil influences the control effect of wheat head blight, wheat yield, prothioconazole residues, and mycotoxin deoxynivalenol (DON) content. Adding 1.0% aviation spray adjuvant to the spray solution can significantly increase the droplet density and deposition amount in different layers of wheat canopy. The wheat yield increased by 6.94% compared with the treatment areas without spray adjuvant. Meanwhile, the prothioconazole and DON mycotoxin were not detected in the wheat grains. Based on these results, we conclude that the addition of aviation spray adjuvant can also not only ensure the high control effect of prothioconazole on FHB in wheat and increase wheat yield, but also greatly reduce the content of DON mycotoxin and ensure the safety of wheat production. This study is expected to provide theoretical guidance and data support for applying spray adjuvants in the field of plant protection UAVs in modern intensive sustainable agriculture.

Antifungal Peptides and Proteins to Control Toxigenic Fungi and Mycotoxin Biosynthesis

The global challenge to prevent fungal spoilage and mycotoxin contamination on food and feed requires the development of new antifungal strategies. Antimicrobial peptides and proteins (AMPs) with antifungal activity are gaining much interest as natural antifungal compounds due to their properties such as structure diversity and function, antifungal spectrum, mechanism of action, high stability and the availability of biotechnological production methods. Given their multistep mode of action, the development of fungal resistance to AMPs is presumed to be slow or delayed compared to conventional fungicides. Interestingly, AMPs also accomplish important biological functions other than antifungal activity, including anti-mycotoxin biosynthesis activity, which opens novel aspects for their future use in agriculture and food industry to fight mycotoxin contamination. AMPs can reach intracellular targets and exert their activity by mechanisms other than membrane permeabilization. The mechanisms through which AMPs affect mycotoxin production are varied and complex, ranging from oxidative stress to specific inhibition of enzymatic components of mycotoxin biosynthetic pathways. This review presents natural and synthetic antifungal AMPs from different origins which are effective against mycotoxin-producing fungi, and aims at summarizing current knowledge concerning their additional effects on mycotoxin biosynthesis. Antifungal AMPs properties and mechanisms of action are also discussed.

Nanoencapsulation-Based Edible Coating of Essential Oils as a Novel Green Strategy Against Fungal Spoilage, Mycotoxin Contamination, and Quality Deterioration of Stored Fruits: An Overview

Currently, applications of essential oils for protection of postharvest fruits against fungal infestation and mycotoxin contamination are of immense interest and research hot spot in view of their natural origin and possibly being an alternative to hazardous synthetic preservatives. However, the practical applications of essential oils in broad-scale industrial sectors have some limitations due to their volatility, less solubility, hydrophobic nature, and easy oxidation in environmental conditions. Implementation of nanotechnology for efficient incorporation of essential oils into polymeric matrices is an emerging and novel strategy to extend its applicability by controlled release and to overcome its major limitations. Moreover, different nano-engineered structures (nanoemulsion, suspension, colloidal dispersion, and nanoparticles) developed by applying a variety of nanoencapsulation processes improved essential oil efficacy along with targeted delivery, maintaining the characteristics of food ingredients. Nanoemulsion-based edible coating of essential oils in fruits poses an innovative green alternative against fungal infestation and mycotoxin contamination. Encapsulation-based coating of essential oils also improves antifungal, antimycotoxigenic, and antioxidant properties, a prerequisite for long-term enhancement of fruit shelf life. Furthermore, emulsion-based coating of essential oil is also efficient in the protection of physicochemical characteristics, viz., firmness, titrable acidity, pH, weight loss, respiration rate, and total phenolic contents, along with maintenance of organoleptic attributes and nutritional qualities of stored fruits. Based on this scenario, the present article deals with the advancement in nanoencapsulation-based edible coating of essential oil with efficient utilization as a novel safe green preservative and develops a green insight into sustainable protection of fruits against fungal- and mycotoxin-mediated quality deterioration.

Deoxynivalenol damages the intestinal barrier and flora of the broiler chickens

BackgroundIn livestock feed industry, feed and feed raw materials are extremely susceptible to mycotoxin contamination. Deoxynivalenol (DON) is one of the main risk factors of mycotoxin contamination in broiler feed and feedstuff, however, there are still few knowledges about tihs. Hence, the purpose of this study was to explore that the toxicity effect of DON on the intestinal barrier of broiler chickens and the microecological balance of the flora.ResultsIn our present study, we compared the pathological scores of the small intestines of broilers on the 5th, 7th and 10th day, and chose the 7th day to analyze the small intestine histomorphology, tight junctions and cecal flora of the broilers. The results showed the damage to the small intestine worsened over time, the small intestinal villi of broilers were breakaged, the tight junctions of the small intestine were destroyed, the cecal flora was unbalanced, and the growth performance of broilers was reduced on the 7th day.ConclusionsDON could damage the functional and structural completeness of intestinal tract, disorder the Intestinal flora, and finally lead to declined broiler’s performance. Our study provided a basis for the prevention and treatment of DON in broiler production.

69 Occurrence of Mycotoxins in 2020 US Corn Grain and Corn By-product Feeds

Mycotoxins are fungal metabolites that limit animal health and performance through various negative effects including reduced feed intake, diarrhea, and compromised immune function. These toxic metabolites have been detected in a broad range of feedstuffs worldwide. This study investigated mycotoxin occurrence and contamination levels in U.S. corn grain samples marked as 2020 harvest year and corn by-product feed samples submitted since October 2020. Samples were screened via LC-MS/MS for six major mycotoxin groups including: aflatoxins, type A trichothecenes, type B trichothecenes (B-Trich), fumonisins (FUM), zearalenone (ZEN), and ochratoxin A. Results from samples that were above the limit of detection for each respective mycotoxin group were analyzed using the GLIMMIX procedure (SAS 9.4, Cary, NC) to test the effect of harvest year on mean contamination level. Results are presented in Table 1. Occurrence levels of B-Trich, ZEN, and FUM in 2020 corn grain are numerically lower than those from 2019. Mean B-Trich level (parts per billion, ppb) for corn grain samples harvested in 2020 was similar to 2019 crop year. Contamination levels of FUM and ZEN were similar for 2020 crop as compared to prior harvest years. Mycotoxin occurrence in corn by-product feeds continued to be high at 99, 85, and 95% for B-Trich, ZEN, and FUM, respectively. Mean B-Trich and ZEN levels in 2020 corn by-products were similar to respective contamination levels in 2018, but were lower than 2019 samples. Mean FUM contamination in corn by-products has been similar across reported years. Preliminary results of the 2020 corn grain survey indicate mean mycotoxin contamination levels are similar to those observed the past two crop years while levels of B-Trich and ZEN in corn by-product feeds are reduced from 2019. Corn-based feed ingredients may present challenges to producers due to the presence of mycotoxin contamination, therefore, continued monitoring is warranted.