Toxigenic mycobiota and mycotoxins in shrimp feed/Micobiota toxigena e micotoxinas em racao de camarao

The objective of this study was to identify the toxigenic mycobiota and the occurrence of aflatoxins in shrimp feed products intended for shrimp cultivated in the coastal area of the state of Piaui, Brazil, in three farms ("A", "B" and "C"). The toxigenic capacity of the fungal species isolated was tested for aflatoxins (AF) and ochratoxin A production. The fungal counts of shrimp feed were similar for the "A" and "B" farms at all cultivation phases, collection sites, in closed and opened packages (1.33 to 2.66CFU [g.sup.1] [log.sub.10.sup.-1]). The lowest fungal counts were found in feed from "C" farm (0.65CFU [g.sup.1] [log.sub.10.sup.-1]) from closed packages. Thirty-four strains of Aspergillus were detected with a greater prevalence of A. flavus. Two strains produced B1, B2, G1 and G2 aflatoxins at concentrations from 0.39 to 0.42ng [g.sup.1]; 0.18 to 0.27ng [g.sup.1]; 1.78ng [g.sup.1] and 0.09ng [g.sup.1] respectively and were classified as atypical A. flavus. Two strains of A. niger aggregate were OTA producers. Fifteen samples (13.88%) presented AFB1 contamination at levels ranging from 0.25ng to 360ng [g.sup.1]. This study demonstrates the presence of toxigenic fungi in shrimp feed used at different phases of cultivation and farms. Atypical strains of A. flavus were isolated which produced AF B1, B2, G1 and G2 in shrimp feeds. Only AFB1 was detected in the analyzed feed. Key words: Litopenaeus vannamei, feed storage, toxigenic fungi, mycotoxins, aflatoxin B1. O objetivo deste estudo foi identificar a micobiota toxigenica e a incidencia de aflatoxinas em racoes comerciais para camarao cultivado no litoral do Estado do Piaui, Brasil, em tres fazendas ("A", "B" e "C"). Foi realizada a capacidade toxigenica das especies de fungos isolados e a producao de aflatoxinas (AF) e ocratoxina A (OTA). As contagens fungicas da racao foram semelhantes nas fazendas "A" e "B" e em todas as fases de cultivo, locais de coleta e de embalagens fechadas e abertas (1,33-2,66UFC [g.sup.1] [log.sub.10.sup.-1]). As mais baixas contagens de fungos foram encontradas nas racoes de embalagens fechadas da fazenda "C" (0,65UFC [g.sup.1] [log.sub.10.sup.-1]). Foram isoladas trinta e quatro cepas de Aspergillus com maior prevalencia de A. flavus e duas linhagens eram produtoras de aflatoxinas B1, B2, G1 e G2 em concentracoes 0,39-0,42ng [g.sup.1]; 0,18-0,27ng [g.sup.1]; 1,78ng [g.sup.1], e 0,09ng [g.sup.1], respectivamente, e foi classificado como A. flavus atipico, sendo necessari