Luiz Antonio Moura Keller

Zearalenone and Its Derivatives α-Zearalenol and β-Zearalenol Decontamination by Saccharomyces cerevisiae Strains Isolated from Bovine Forage

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 observed but a small amount of β-ZOL (6%) disappeared from culture medium. ZEA biotransformation by yeasts may not be regarded as a full detoxification process because both main end-products are still estrogenic. Nonetheless, it was observed that the biotransformation favors the formation of β-ZOL which is less estrogenic than ZEA and α-ZOL. This metabolic effect is only possible if active strains are used as feed additives and may play a role in the detoxification performance of products with viable S. cerevisiae cells.

Incidence of Mycotoxins (AFB1 and AFM1 ) in Feeds and Dairy Farms from Rio de Janeiro State, Brazil

Brazil has regions located at the largest dairy production and milk derivate industry concentration, supplying the major consumer markets, represented by São Paulo, Rio de Janeiro and Belo Horizonte Cities. The milk is the most important product of Brazilian agriculture, because it is always presents in daily diet. The aim of this research was evaluating the occurrence of mycotoxins in the feed of dairy cattle and the occurrence of AFM1 in milk under field conditions in farms from Rio de Janeiro State, Brazil. The results revealed that, total fungal counts was found in 67% of feed samples which exceeded the recommended limit recommended (1×104 UFC.g-1) and the incidence of AFM1 in all milk samples was 26.7% at concentrations ranging from 0.010 to 1.500 μg.L-1. The study revealed toxigenic fungi and their mycotoxins were present in feed intended for bovine feeding in Rio de Janeiro farms. Evaluations of mycotoxin levels are important to provide information so that the assessments of risk for animal feed and livestock environment can be done.