Zearalenone (ZEA) and its derivatives are mycotoxins with estrogenic effects on mammals. The biotransformation for ZEA in animals involves the formation of two major metabolites, α- and β-zearalenol (α-ZOL and β-ZOL), which are... more
Zearalenone (ZEA) and its derivatives are mycotoxins with estrogenic effects on mammals. The biotransformation for ZEA in animals involves the formation of two major metabolites, α- and β-zearalenol (α-ZOL and β-ZOL), which are subsequently conjugated with glucuronic acid. The capability of Saccharomyces cerevisiae strains isolated from silage to eliminate ZEA and its derivatives α-ZOL and β-ZOL was investigated as, also, the mechanisms involved. Strains were grown on Yeast Extract-Peptone-Dextrose medium supplemented with the mycotoxins and their elimination from medium was quantified over time by HPLC-FL. A significant effect on the concentration of ZEA was observed, as all the tested strains were able to eliminate more than 90% of the mycotoxin from the culture medium in two days. The observed elimination was mainly due to ZEA biotransformation into β-ZOL (53%) and α-ZOL (8%) rather than to its adsorption to yeast cells walls. Further, the biotransformation of α-ZOL was not obser...
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The aim of the study was to determine the mycobiota and natural levels of mycotoxins such as aflatoxin B1 (AFB1), ochratoxin A (OTA), fumonisin B1 (FB1), and deoxynivalenol (DON) present in brewers grains pre- and poststored intended for... more
The aim of the study was to determine the mycobiota and natural levels of mycotoxins such as aflatoxin B1 (AFB1), ochratoxin A (OTA), fumonisin B1 (FB1), and deoxynivalenol (DON) present in brewers grains pre- and poststored intended for bovine intensive rearing. Poststored (80%) samples had counts higher than 1 × 10(4) colony-forming units (CFU/g). Cladosporium spp. and Aspergillus spp. were isolated at high frequencies. Aspergillus flavus was the prevalent isolated species. Prestored (70%) and poststored (100%) samples showed AFB1 levels over the recommended limits (20 μ g/Kg), and OTA levels were below the recommended limits (50 μ g/Kg) while pre- and poststored samples did not show FB1 and DON natural contamination levels. The presence of mycotoxins in this substrate indicates the existence of contamination. Regular monitoring of feeds is required in order to prevent chronic and acute toxic syndromes related to this kind of contamination.
The aim of this study was to determine total fungal counts and the relative density of Aspergillus fumigatus and related species in silage samples intended for bovines before and after fermentation as well as to monitor the natural... more
The aim of this study was to determine total fungal counts and the relative density of Aspergillus fumigatus and related species in silage samples intended for bovines before and after fermentation as well as to monitor the natural occurrence of gliotoxin in silage samples (pre- and postfermentation). The survey was performed in farms located in São Paulo and Rio de Janeiro States in Brazil. In addition, the ability of A. fumigatus strains and related species strains to produce gliotoxin was also evaluated. A total of 300 samples were taken, immediately after opening of the silo (3-5 months) and during the ensiling period. Fungal counts were done by the surface-spread method. Gliotoxin production ability of isolates and natural contamination were determined by HPLC. All postfermented samples had a total number of moulds exceeding 1 × 10(4) CFU g(-1), with Aspergillus sp. as the most prevalent genus. Frequency of strains, among A. fumigatus and related species, was able to produce gl...
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The harmful effects of fungi in sorghum silage are an important matter in many countries with hot climates. This culture is very susceptible to fungal contamination and both the storage and processing of this substrate are ideal for the... more
The harmful effects of fungi in sorghum silage are an important matter in many countries with hot climates. This culture is very susceptible to fungal contamination and both the storage and processing of this substrate are ideal for the development of fungi there are able to produce mycotoxins. The contamination with mycotoxins, secondary products of the metabolism of certain fungi, that promotes risks to both animal and human health, causes numerous losses for the country. The aim of this study was to identify the toxicogenic fungi present in sorghum silage for beef cattle consumption and determine the occurrence of aflatoxin B1 (AFB1) in the same substrate. A total of 60 pre-fermented and 60 post-fermented samples of sorghum silage were analyzed. Total fungal counts and natural incidence of toxigenic Aspergillus, Penicillium y Fusarium species were performed on dichloran rose bengal chloranphenicol agar, dichloran glycerol agar 18 % and Nash-Snyder culture media. Aflatoxin B1 cont...
The present revision shows the early and current knowledge in the field of silage fungi and mycotoxins explaining the relevance of fungi and mycotoxins in silage. The problem does not end in animal disease or production losses as... more
The present revision shows the early and current knowledge in the field of
silage fungi and mycotoxins explaining the relevance of fungi and mycotoxins
in silage. The problem does not end in animal disease or production losses as
mycotoxins in feed can lead to the presence of their metabolic products in
dairy products, which will be eventually affecting human health, mainly
infants. Silage is green forage preserved by lactic fermentation under anaerobic
conditions. This ecosystem maintains its quality and nutritional value
depending on interactions among physical, chemical and biological agents.
Forages used for ensilage are naturally in contact with yeasts and filamentous
fungi, and the contamination often occurs in the field and can also occur
during harvesting, transport, storage. Moreover, postharvest poor management
can lead to a rapid spoilage. Studies on fungal contamination of dairy cattle
feed have shown how corn silage influences the contamination degree of feed
supplied to livestock. Increasing knowledge in this area will help elucidate the
influence that this microbiota exerts on production and/or degradation of
mycotoxins present in silage. Some of these fungi, although opportunist
pathogens, are relevant epidemiologically and represent a high risk of
contamination to farm workers who handle them improperly.
silage fungi and mycotoxins explaining the relevance of fungi and mycotoxins
in silage. The problem does not end in animal disease or production losses as
mycotoxins in feed can lead to the presence of their metabolic products in
dairy products, which will be eventually affecting human health, mainly
infants. Silage is green forage preserved by lactic fermentation under anaerobic
conditions. This ecosystem maintains its quality and nutritional value
depending on interactions among physical, chemical and biological agents.
Forages used for ensilage are naturally in contact with yeasts and filamentous
fungi, and the contamination often occurs in the field and can also occur
during harvesting, transport, storage. Moreover, postharvest poor management
can lead to a rapid spoilage. Studies on fungal contamination of dairy cattle
feed have shown how corn silage influences the contamination degree of feed
supplied to livestock. Increasing knowledge in this area will help elucidate the
influence that this microbiota exerts on production and/or degradation of
mycotoxins present in silage. Some of these fungi, although opportunist
pathogens, are relevant epidemiologically and represent a high risk of
contamination to farm workers who handle them improperly.