Avalia??o micol?gica e micotoxicol?gica de silagens destinadas ? alimenta??o de bovinos de fazendas no Estado de S?o Paulo e Rio de Janeiro

• Autor(a) principal: Keller, Luiz Antonio Moura
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/tede/783
• topic: micotoxinas; fungos; milho; mycotoxins; fungi; corn; Medicina Veterin?ria

Despite having the second largest cattle herd in the world, the Brazilian has low rates of productivity. The performance of the animals in pastures is reasonable during the rainy season, being deficient in the dry season, caused by the low availability and quality of grass, which results in weight loss of animals. Thus ensiled foods are a recently solution to this situation in the production process. But we have a very few studies on this food substrate in Brazil and Latin America. The objectives of this study were to establish the natural frequency of species from the genera Aspergillus, Penicillium and Fusarium potentially mycotoxins producers and detect mycotoxins presents in the samples (aflatoxins, ochratoxin A, fumonisin B1 and deoxynivalenol). It was observed that the post-fermented substrates had 70% of samples contaminated above the limits recommended for feeding of 1.0 x 10 ufc.g (GMP, 2008), thus it was observed that the bad hygienic quality and high counts led to a variable and potentially toxigenic micobiota. Aspergillus flavus is the species of greatest occurrence in the samples evaluated, followed by A. niger aggregate, A. fumigatus, A. parasiticus, and other species of this genera. In genera Aspergillus, when strains were tested against their ability to produce toxins under appropriate conditions had an output of at least 30% of the strains potential toxigenic. Add to this fact that the detection of high levels of toxins produced by this genera, aflatoxins (levels above 70 ppb) and ochratoxin A (up to 10 ppm). The genera Penicillium had also variability of the species isolated, with a higher frequency of strains from post-fermented material, the kind that most stood out was the P. citrinum, the main producer of citrinin, which have demonstrated capacity to produce that toxin in 75% of the strains. The Fusarium sp. showed a low variability of species in the samples evaluated, even in pre-fermented samples where counts were higher and had the occurrence of only two species F. verticillioides and F. graminearum. Moreover, were also detected low frequency and levels of toxins from this genus (0,32-2 ppm levels of FB14-1 and levels of 0,56-2 ppm of DON). This observation creates the need to expand studies related to ensiled food, which the animals were feed during major periods of the year.