Incidence of Aspergillus fumigatus and potenciality of gliotoxin production in animal feed intended to domestic animals and pets

PENA G.; PEREYRA C.; ASTORECA A.; DALCERO A.; ROSA C.A.R.; CAVAGLIERI L.

Holanda

Congreso; The Wordl Mycotoxin Forum; 2008

The fungal invasion of raw materials and the consequent formation of mycotoxins are considered a potential risk factor for food quality. In previous studies carried out by our research group showed the presence of the main toxicogenic fungi (Aspergillus, Penicillium and Fusarium) and its associated mycotoxins (aflatoxin, zearalenone and fumonisins) in poultry, pigs and rabbits feeds (Dalcero et al., 1997, 1998, 2002; Magnoli et al., 1998, 1999, 2002). This pollution reduces the nutritional value of foods and can affect animal health with serious economic losses in meat and milk products. The mycotoxins of A. fumigatus and P. roqueforti species have not only been detected under experimental conditions but also in analysis of samples of field (Auerbach et al., 1998). In previous studies showed the A. fumigatus prevalence respect to the other toxigenic species present in silage and finished food destined to bovine consume subjected to intensive breeding (Cavaglieri et al., 2005). The gliotoxin, main metabolite produced by A. fumigatus is a potent inmunosupresor with genotoxic, citotoxic and apoptotic effects (Upperman et al., 2003). In Argentina there are no data about contamination with A. fumigatus and/or their toxins into silage, raw materials and finished foods destined to consumption of domestic animals and pets. The aim of this study was to evaluate the incidence of A. fumigatus and its capacity to produce gliotoxin in food destined to domestic animals and pets. The isolation and identification of the contaminant mycobiota was carried out according to the keys proposed by Pitt and Hocking, (1997) and Klich (2002). For the determination of the capacity to produce gliotoxin by A. fumigatus strains isolated from silage, raw materials and finished foods followed the methodology described by Davis et al., (1963) and Boudra and Morgavi (2005). In general, silage samples analysed contain counts that ranged from 1.75 x 105 to 9.35 x 107 CFU/g, showing a high degree of fungal contamination. The total count of finished food samples showed levels between ND (not detected) at 2.85 x 107 CFU/g. The total fungal count in silage and finished food analyzed exceeded the levels proposed as a quality limit, which stablish that the fungal contamination should not exceed 1 x 104 CFU/g for all ingredients and supplies destined to animal feed (GMP, 2005). The mycological survey showed the presence of 9 genus of filamentous fungi and yeast. Six species of Aspergillus were identified. The prevalent species was A. flavus with a isolation frequency of 53.4%. The isolation frequency of A. fumigatus was higher in the finished food (40%) than in corn silage (20%). Other studies have shown the presence of A. fumigatus in silage as prevalent species (Garon et al., 2006). 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