Carlos Alberto da Rocha Rosa

Detection of ochratoxin A in animal feeds and capacity to produce this mycotoxin by Aspergillus section Nigri in Argentina

Ochratoxin A (OA) is a mycotoxin detected in a variety of food and feeds mostly from countries with a temperate climate because of the fungi that produce it, mainly Aspergillus ochraceus and Penicillium verrucosum. In Argentina, there is no available information about the natural occurrence of OA and ochratoxigenic fungi from feedstuffs. The aim was to evaluate the natural occurrence of OA in poultry, pig and rabbit feeds over 8 months. Likewise, the capacity to produce OA by Aspergillus section Nigri was investigated. Mycotoxin analysis showed that in some months of sampling, OA was detected in three feeds. OA was found in 38% of the poultry feed samples tested with levels ranging from 25 to 30 ng g−1. From rabbit feed samples, 25% contained OA and the levels ranged from 18.5 to 25 ng g−1. Only 13% of the pig feed samples were contaminated with similar levels of toxins. Ninety-four black Aspergillus strains from feedstuffs were tested for OA production. Among these, the tested species were A. niger var. niger, A. niger var. awamori, A. japonicus var. japonicus, A. japonicus var. aculeatus and A. foetidus. For the detection of OA, three methodologies were applied: the two TLC methods used for the fast screening of the filamentous fungi for the production of OA were not sensitive enough to detect OA in any of the black Aspergillus strains. When an HPLC methodology was used, the results showed that 46% of the black Aspergillus strains were producers of OA, with levels ranging from 13 to 25 ng ml−1 culture medium. The highest percentage of ochratoxicogenic strains was isolated from rabbit feeds with 100 and 78% of A. niger var. niger and A. niger var. awamori, with mean levels of 15.5 and 14.6 ng ml−1, respectively. From pig feeds, 61% of the A. niger var. awamori were producers of this toxin with mean levels of 16 ng ml−1. In poultry feeds, the lowest percentage of OA producer strains was detected. The results for the occurrence of OA in feeds from different sampling months depended on storage and humidity-temperature conditions. Therefore, a good storage practice becomes very important to prevent OA production

Survey of mycoflora and ochratoxin A in dried vine fruits from Argentina markets

Aims:  The aims of this work were to identify the mycoflora and to evaluate the natural occurrence of OA in dried vine fruits. Likewise, the capacity to produce OA by Aspergillus section Nigri was studied.

Occurrence of ochratoxin A in wine and grape juice marketed in Rio de Janeiro, Brazil

Ochratoxin A (OA) is receiving attention world-wide because of the hazard it poses to human health. The aim was to test the distribution of OA in grape juice, pulps of frozen grapes, and national and imported table wine obtained from markets in Rio de Janeiro, Brazil. Analytical methodology using immunoaffinity column for OA extraction and clean-up with a final separation on a reversed-phase (C18) column and fluorescence detection in high-performance liquid chromatography showed a detection limit of 21 ng l−1. The mean recovery was 91% for red wines and 82% for white wines; while the mean recoveries for juices and pulps of frozen grapes were 91.6 and 88%, respectively. Of 64 samples of grape juice and frozen pulps, 25% were positive for OA, being the mean content of 37 ng l−1 with a maximum concentration of 100 ng l−1. In wines, the mean concentration detected in 80 samples analysed was 34.4 ng l−1 with 28.75% of positive samples. Red wines showed the highest percentages and levels of contaminated samples: 38% and 37 ng l−1, respectively. The white wine contained levels above 26 ng l−1 in 17.75% of the analysed samples. The levels of contamination detected in red wine sold in Río de Janeiro were not enough to surpass the virtually safe dose established as 5 n g kg−1 body weight of daily intake.

Fungi and selected mycotoxins from pre- and postfermented corn silage

Aim:  To determine fungal genera, Aspergillus and Fusarium species and aflatoxin B1 (AFB1), zearalenone (ZEA), deoxynivalenol (DON), fumonisin B1 (FB1) contamination from pre‐ and postfermented corn silage produced in the most important region of Argentina where silage practice is developed.

Determination of mycobiota and mycotoxins in pig feed in central Argentina

Aims:  To evaluate the mycobiota and natural levels of aflatoxins, fumonisins and zearalenone present in compound feed and home‐corn grains intended for fattening pigs.

Gliotoxin natural incidence and toxigenicity of Aspergillus fumigatus isolated from corn silage and ready dairy cattle feed

Corn silage is an important feed source for dairy and beef cattle in central Argentina. The presence of thermophilic species Aspergillus fumigatus is among the major problem in silage, as many strains can produce several mycotoxins that affect the health of dairy cattle. The aims of the present study were to determine total fungal counts and relative density of A. fumigatus in silage samples, and to determine the natural incidence of gliotoxin in silage and ready dairy feed samples. The potential gliotoxin production of A. fumigatus isolated from silage was also recorded. A total of 90 samples were investigated, which were taken immediately after opening of the silo and the end of the ensiling period of about after 5 months. Sampling was performed manually through silos in transects at 3 levels per silo. Thirty samples of ready cattle feed (corn silage, ground corn, barley, cotton seed, brewer grains) were collected and investigated as well. Gliotoxin contamination was determined by HPLC. The ability of A...

Influence of water activity, temperature and time on mycotoxins production on barley rootlets

Aims:  The objective of this study was to determine the ochratoxin (OT) and aflatoxin (AF) production by three strains of Aspergillus spp. under different water activities, temperature and incubation time on barley rootlets (BR).

Sodium bentonite and monensin under chronic aflatoxicosis in broiler chickens

Clay feed additives have been increasingly incorporated into animal diets to prevent aflatoxicosis. Due to the nonselective nature of the binding interaction, many important components of the diets could also be made unavailable because of these feed additives. The anticoccidial monensin (MON) could also be sequestered by these clays. The use of sodium bentonite (Na-B) from a mine in the province of Mendoza, Argentina, was investigated as a sequestering agent to prevent the effects of 100 µg/kg of dietary aflatoxin B(1) (AFB(1)). In vitro studies demonstrated that the above Na-B was a good candidate to prevent aflatoxicosis. They also showed that MON competes with AFB(1) for the adsorption sites on the clay surface and effectively displaces the toxin when it is in low concentration. Even though the levels of MON in diets, approximately 55 mg/kg, are high enough to not be significantly changed as a consequence of the adsorption, they can further affect the ability of the clays to bind low levels of AFB(1). An in vivo experiment carried out with poultry showed that 100 µg/kg of AFB(1) does not significantly change productive or biochemical parameters. However, liver histopathology not only confirmed the ability of this particular Na-B to prevent aflatoxicosis but also the decrease of this capacity in the presence of 55 mg/kg of MON. This is the first report stressing this fact and further research should be performed to check if this behavior is a characteristic of the assayed Na-B or of this type of clay. On the other hand, the presence of MON should also be taken into account when assaying the potential AFB(1) binding ability of a given bentonite.

The Mycobiota and Toxicity of Equine Feeds

Feed contamination can lead to nutrient losses and detrimental effects on animal health and production. The purposes of this study were to investigate the mycobiota in equine mixed feeds and to determine natural contamination with aflatoxin B1 (AFB1) and fumonisin B1 (FB1). Fungal enumeration of equine feed samples was done. A commercially available enzyme-linked immunosorbent assay kit was applied to quantify AFB1 and FB1. A comparison between ELISA and HPLC was carried out. Feed mould counts ranged from <1× 102 to 1× 105 cfu/g. The most frequent genus isolated was Aspergillus (40.54%), followed by Penicillium (18.38%) and Fusarium (16.22%). The most prevalent Aspergillus sp. was A. flavus (36%). AFB1 values ranged between 0.01 and 99.4 μg/kg. FB1 levels ranged between 0.01 and 7.49 μg/kg. HPLC and ELISA methods showed positive correlation for AFB1 and FB1 determinations (r = 0.9851 and r = 0.9791, respectively). The ELISA analytical method was efficient for AFB1 and FB1 detection. The scarcity of studies on natural fungal contamination and on the presence of AFB1 and FB1 in materials used as equine feed ingredients highlights the value and contribution of this study.

Mycobiota and aflatoxins in raw materials and pet food in Brazil

Commercial feedstuffs are a basic element in modern pet husbandry in the world. In dogs, the effect of mycotoxins is severe and can lead to death. Few reports on the influence of dietary mycotoxins were found in the scientific literature. The aims of this work were to isolate and identify the mycoflora and to determine the aflatoxins (AFs) natural occurrence in raw materials and ready dry pet food. Therefore, the aflatoxigenic capacity of Aspergillus flavus species was investigated. Aspergillus was the prevalent genera (65-89%) followed by Penicillium and Fusarium spp. Aspergillus flavus was the most prevalent species, followed by Aspergillus sydowii, Aspergillus fumigatus and Aspergillus versicolor. Aspergillus flavus frequencies ranged from 58% to 86% except in sorghum meal. All samples assayed (except corn grains and ready pet food) showed Fusarium spp. contamination. Corn meal and corn meal and gluten samples had 100% Fusarium verticillioides. Fusarium graminearum was isolated from sorghum meal. Aspergillus flavus strains (75%) isolated from raw materials and 57% from pet food were able to produce AFs. All samples showed AFs contamination percentages over 70%; corn and sorghum meal obtained the highest AFs levels. Ready pet food did not show quantitative levels of the tested toxins. This is the first report of the aflatoxigenic capacity by A. flavus from Brazilian pet food.