RESUMO
Fusarium species can produce fumonisins (FBs), fusaric acid, beauvericin (BEA), fusaproliferin (FUS) and moniliformin. Data on the natural occurrence of FBs have been widely reported, but information on BEA and FUS in maize is limited. The aims of this study were to establish the occurrence of Fusarium species in different maize hybrids in Mexico, to determine the ability of Fusarium spp. isolates to produce BEA, FUS and FBs and their natural occurrence in maize. Twenty-eight samples corresponding to seven different maize hybrids were analyzed for mycobiota and natural mycotoxin contamination by LC. Fusarium verticillioides was the dominant species (44-80%) followed by F. subglutinans (13-37%) and F. proliferatum (2-16%). Beauvericin was detected in three different hybrids with levels ranging from 300 to 400 ng g(-1), while only one hybrid was contaminated with FUS (200 ng g(-1)). All samples were positive for FB1 and FB2 contamination showing levels up to 606 and 277 ng g(-1), respectively. All F. verticillioides isolates were able to produce FB1 (13.8-4,860 µg g(-1)) and some also produced FB2 and FUS. Beauvericin, FUS, FB1 and FB2 were produced by several isolates including F. proliferatum and F. subglutinans and co-production was observed. This is the first report on the co-occurrence of these toxins in maize samples from Mexico. The analysis of the presence of multiple mycotoxins in this substrate is necessary to understand the significance of these compounds in the human and animal food chains.
RESUMO
The aim of this study was to evaluate the chemical composition, mold count and mycotoxin contamination of corn silage collected during a six month-period. The results indicated that the chemical composition and the physicochemical parameters evaluated did not show significant variation during the sampling time. Fungal count on RBC ranged from 1.7 x 10(3) to 9 x 10e8 CFU/g. Mucor, Penicillium and Aspergillus spp. were the most frequent fungal species in the corn silage. Fusarium count ranged from 1.6 x 10(3) to 1.6 x 10e8 CFU/g in Nash Snyder culture media. Aflatoxin B, fumonisins, ochratoxin A, ochratoxin B, deoxynivalenol, and zearalenone were detected throughout the period of corn silage maintenance (100% positive samples). However, only deoxynivalenol levels were higher than the maximum limit recommended by the FDA.
Assuntos
Micotoxinas/análise , Silagem/análise , Silagem/microbiologia , Zea mays/química , Zea mays/microbiologiaRESUMO
The objective of the work was to study H. irritans population fluctuation in a cattle herd in Tecoman, Colima, Mexico. The cattle herd was visited weekly from March 2003 to May 2004; on each occasion, ten animals were randomly selected to estimate infestation by direct visualization method. Temperature and relative humidity (RH) were recorded daily. Population fluctuation was described and periods and population peaks were identified. Pearson's correlation analysis was calculated (P < 0.05) between temperature and RH, with fly average number per animal for each population period. H. irritans infestation had fluctuations, but with presence of flies all the year; the highest infestation was observed in summer, where two population peaks were present, with 236 and 120 flies per animal, respectively; the activity in autumn and winter also showed fluctuations and the population had an increment in spring, where a population peak could be observed, as well as at the beginning of the study (156 flies/animal) and at the end (323 flies/animal). In the first population period, a significant correlation coefficient (0.93) was found with temperature, similar situation was observed in the fourth period (-0.57); no significant coefficients were found in other population periods for the climatic factors in study.
El objetivo del trabajo fue estudiar la fluctuación poblacional de H. irritans en un hato de ganado bovino en el municipio de Tecomán, Colima, México. El hato fue visitado semanalmente de marzo de 2003 a mayo de 2004; en cada ocasión se seleccionaron al azar diez animales para estimar la infestación mediante el método de visualización directa. Se registró la temperatura y la humedad relativa (HR) diariamente. Se describió la fluctuación poblacional presentada y se identificaron los periodos y picos poblacionales. Se realizó un análisis de correlación de Pearson (P < 0.05) entre la temperatura y la HR, con los valores promedio del número de moscas por animal para cada uno de los periodos poblacionales. La infestación por H. irritans fue fluctuante, pero con presencia de moscas durante todo el año; los momentos de mayor infestación se observaron en verano, al presentarse dos picos poblacionales, con 236 y 120 moscas/animal; la actividad en otoño e invierno también fluctuó; se incrementó en primavera, durante la cual se observó un pico poblacional, tanto al inicio del estudio (156 moscas/animal) como al final (323 moscas/animal). Para el primer periodo poblacional se encontró un coeficiente de correlación significativo (0.93) con la temperatura, algo similar ocurrió para el cuarto periodo (-0.57); no fue posible detectar coeficientes significativos en otros periodos poblacionales para los factores climáticos en estudio.