ISOLATION OF MYCOBIOTA AND INCIDENCE OF MYCOTOXINS IN POULTRY FEEDS IN ARGENTINA

C. E. MAGNOLI; E.A. RAMIREZ; R. MIAZZO; S.M. CHIACCHIERA; A. M. DALCERO

Guarujá

Simposio; X International IUPAC Symposium on micotoxins and phycotoxins.; 2000

Instituto Adolfo Lutz, San Pablo, Brasil

The aim of this work was to continue with the incidence of toxigenic fungi and their mycotoxins on poultry feeds during a period of thirteen months starting from may 1998. The samples of poultry feeds were collected from a factory located in the department of Río Cuarto, Córdoba province, Argentina. A total 130 samples (10 samples per month) were collected from May 1998 to May 1999. Quantitative enumeration of fungal propagules was done on solid media using the surface-spread method. The cultures media were dichloran-rose-bengal-chloranphenicol agar (DRBC) and Nash-Snyder medium. The results were expressed as cfu per gram of sample. Fungal colonies were selected for identification according to the methods proposed for each genus. Determination of aflatoxins and fumonisins were performed by HPLC and zearalenone and deoxynivalenol analyses were performed by TLC. Mycological survey of 130 samples indicated the presence of 15 genera of filamentous fungi. The most prevalent genera isolated were Penicillium spp, Fusarium spp (67,5%) and Aspergillus spp (57,5%). From the Penicillium genus, P. minioluteum (17,5%) P. rugulosum (15%) and P. implicatum (10%) were the most common. Among Aspergillus spp and Fusarium spp, A. flavus (27,5%) , F. moliliforme (42,5%) and F. nygamai (35%) were the most frequent, respectively. Fungal counts in the DRBC medium ranged from 1.7 x 103 to 3.2 x 105 cfu/g. Mycotoxin analysis of these samples, showed that fumonisin incidence was very high, this mycotoxin being detected in 126 (97%) of the samples, followed by AFB1, which was found in 60 (46%) of the samples. The mean levels varied between 139 to 3550 ppb and 15 to 180 g/kg for FB1 and AFB1, respectively. The toxins ZEN and DON were detected in 18% and 6% of the samples, with levels that varied from 1747 to 4886 and 120 to 133 g/kg, respectively. The fungal counts during some months of sampling, were slightly over 1x105 cfu/g, value that was proposed as a limit to ensure the quality of this feed. Although the FB1 incidence was high, the levels detected in poultry feeds were lower than the values established for this feed (50 ppb). In Argentina, the control of agricultural products contaminated with mycotoxins is done during the marketing period. In the Mercosur Technical Regulations, 20 ng/g was established as the maximum limit for total aflatoxins in this products. The levels of toxins found in these samples were higher than the values established by regulatory agencies.