Horses fed meal contaminated with mycotoxins performing short-term exercises / Efeitos das micotoxinas na performance de equinos submetidos a exercícios de curta duração

This research was carried out to evaluate the effect of mycotoxins on the performance of horses through physiological parameters, and hematology and serum biochemistry analyses. The essay lasted 40 days, with 12 days for adaptation and 28 days of experimentation. In the experimental stage, the horses were distributed in a completely randomized design, with three treatments with four animals each. The treatments used were 0 (control), 50 ppb and 100 ppb of Aflatoxin B1 (AFB1) added to a concentrate in a basal diet. The basal diet contained mycotoxins from feedstuffs naturally contaminated. The exercise test was performed over the 21th day of the experimental stage. The exercise consisted in an interval training test with a warm-up of 17 mins at a trot followed by three gallops of 450m/min. The heart rate was monitored between the gallops. Before the exercise test and immediately after the third gallop, the physiological and blood parameters were evaluated, and continued up to 48 hours after the exercise. The results of the physiological, hematological and biochemical parameters were submitted to analysis of variance (ANOVA) and compared by the Tukey test at 5% of significance. The presence of AFB1 in the diet influenced the alkaline phosphatase activity, which presented higher values in horses fed diet with inclusion of 100 ppb AFB1, suggesting a hepatotoxic activity associated with the others mycotoxins naturally present in the feedstuffs.(AU)

Esta pesquisa foi conduzida para avaliar o efeito de micotoxinas no desempenho de equinos com avaliações fisiológicas e análises hematológicas e da bioquímica sérica. O ensaio durou 40 dias, com 12 dias de adaptação e 28 dias de experimentação. Na fase experimental, os equinos foram distribuídos em delineamento inteiramente casualizado em três tratamentos, com quatro animais cada. Os tratamentos utilizados foram 0 (controle), 50 ppb e 100 ppb de Aflatoxina B1 (AFB1) adicionada ao concentrado de uma dieta basal. A dieta basal continha alimentos naturalmente contaminados por micotoxinas. O teste de desempenho foi executado no 21º dia da fase experimental por meio de teste intervalado consistindo em aquecimento ao trote por 17 minutos, seguido de três galopes de 450m/min. A frequência cardíaca (FC) foi monitorada entre os galopes. Antes do exercício e imediatamente após o terceiro galope, os parâmetros fisiológicos e sanguíneos foram avaliados e continuaram sendo monitorados até 48 horas após o exercício. Os resultados dos parâmetros fisiológicos, hematológicos e bioquímicos foram submetidos à análise de variância (ANOVA) e comparados pelo teste de Tukey a 5% de significância. A presença de AFB1 na dieta influenciou a atividade da fosfatase alcalina, que apresentou valores mais elevadas na dieta com inclusão de 100 ppb de AFB1, sugerindo uma atividade hepatotóxica associada às outras micotoxinas naturalmente presentes nos alimentos.(AU)

Potentiation of the effect of a commercial animal feed additive mixed with different probiotic yeast strains on the adsorption of aflatoxin B1.

This study potentiates the adsorbent effect for aflatoxin B1 (AFB1) of a commercial additive (CA) of animal feed, containing inactive lysate of three Saccharomyces cerevisiae strains, active enzymes, adsorbents and a selenium-amino acid complex, when the additive was mixed separately with three S. cerevisiae strains. Levels of AFB1 of 20 and 50 ng g(-1) were used to determine the binding capacity of different concentrations of CA alone and in the presence of yeast strains, as well as toxin desorption, under gastrointestinal conditions. The viability of yeasts in the presence of CA was evaluated. The results show that the CA did not affect the viability of the yeast strains assayed. CA alone showed a low percentage adsorption. At 20 and at 50 ng g(-1), CA was highly efficient in adsorbing AFB1 when combined with RC016 and RC012 strains respectively. Desorption of AFB1 by CA alone and in combination with the yeasts increased with increasing levels of CA. The results demonstrate the improvement of CA in AFB1 adsorption once it is mixed with live yeasts.

Comparative analysis of the mycobiota and mycotoxins contaminating corn trench silos and silo bags.

BACKGROUND: Silage is one of the most important feed sources for bovines. Mycotoxin contamination of feedstuffs is a worldwide concern. The aim of this study was to compare mycobiota and levels of aflatoxin B1 (AFB1), fumonisin B1 (FB1), deoxynivalenol (DON), zearalenone (ZEA) and patulin (PAT) in corn trench silos and silo bags. RESULTS: Dry matter was higher in trench silos. Counts varied from not detected to 108 CFU g⁻¹ in both trench silos and silo bags. Isolation frequencies of Aspergillus spp. and Fusarium spp. were higher in trench silos, whereas Penicillium spp. was higher in silo bags. Silo bags showed less diversity than trench silos. Strains isolated produced AFB1, FB1 and PAT. In trench silos, AFB1 was the only mycotoxin detected (1-160 µg kg⁻¹). In silo bags AFB1 levels varied from 5.8 to 47.4 µg kg⁻¹. DON was detected in two silo bag samples. CONCLUSION: When handling is adequate the reduction of mould and mycotoxin contamination in silo bags is considerable. This study will enable estimation of the mycotoxicological risk of different ensiling practices and determination of the most adequate method to minimize economic losses and reduce hazard to animal and human health.

An outbreak of acute aflatoxicosis on a chinchilla (Chinchilla lanigera) farm in Argentina.

Chinchillas (Chinehilla lanigera) are known to be very sensitive to aflatoxins, and often a large number of animals die if toxicosis occurs. An outbreak of acute aflatoxicosis on a chinchilla farm in Argentina is described in the present study. A commercial feed suspected of causing the death of 200 animals was sampled. Livers from 9 dead chinchillas were analyzed for their macroscopic and microscopic characteristics via necropsy and histopathology. Aflatoxins B(1), B(2), G(1), and G(2) were determined, by thin layer chromatography, to be in the feed. Macroscopic inspection of livers revealed general enlargement, pale-yellowish coloration, hypertrophy, rounded borders, and increased friability. Size and color were remarkably different from a healthy organ. Histopathologic analyses of hepatic parenchyma showed severe, diffuse cytoplasmic vacuolation of hepatocytes. Sudan III staining confirmed the presence of lipid within the vacuoles. The feed was positive for aflatoxin B(1) in quantities that exceeded the recommended levels. Histologic lesions were typical of aflatoxin intake. Monitoring feed for mycotoxins is crucial to prevent outbreaks of toxicosis, to improve management practices, and to diminish exposure risk of animals and humans to these harmful toxins.