Adsorption of aflatoxin B1 by different antimycotoxin additives: bentonite, clinoptilolite, and beta-glucans extracted from yeast cell wall.

The present study aims to evaluate and compare antimycotoxin additives (AMAs) composed of bentonite (AMA 1), clinoptilolite (AMA 2), and beta-glucans extracted from yeast cell wall (AMA 3), with respect to their ability to bind Aflatoxin B1 (AFB1) using the isothermal models of Freundlich, Langmuir, and BET. The additives were submitted to an in vitro adsorption experiment with AFB1 (0.05-4 mg L-1), using solutions of pH 3 and pH 6, with an inclusion rate of 0.5%, and analyzed by HPLC-MS/MS. At pH 3, for the seven concentrations evaluated, AMA 1 obtained adsorption rates (99.69 to 99.98%) higher (p < 0. 05) than the other AMAs, which were from 82.97 to 88.72% (AMA 2) and from 79.43 to 89.32% (AMA 3). At pH 6, in concentrations of 1, 2, and 4 mg L-1 of AFB1, AMA 1 obtained higher (p < 0.05) adsorption results (97.86 to 99.86%) than AMA 2 (91.98 to 96.12%) and AMA 3 (87.56 to 93.50%). The Freundlich model best fitted the AMA 1 adsorption data. For the other additives, the Langmuir model obtained the best fit, demonstrating qm of 8.6 mg g-1 at pH 3 and 2.3 mg g-1 at pH 6 for AMA 2; and for AMA 3, with qm of 3.4 mg g-1 at pH 3 and 2.3 mg g-1 at pH 6. The isotherm models work as an effective tool to describe the adsorption process whereas the AMA adsorption capacity varies as a function of product composition, pH, and mycotoxin content.

Leptospira spp. in horses in southern Brazil: Seroprevalence, infection risk factors, and influence on reproduction.

Leptospirosis in horses is often associated with reproductive disorders. In the southern states of Brazil, horses are used for various jobs and cultural practices; nevertheless, serological surveillance for Leptospira is rare. Therefore, the objective of this study was to determine the seroprevalence of Leptospira spp. in horses in southern Brazil, as well as to identify the risk factors for infection and its impacts on reproduction. We performed microscopic agglutination tests for 12 serovars that corresponding 9 serogroup (Sejroe, Icterohaemorrhagiae, Australis, Pyrogenes, Pomona, Canicola, Grippotyphosa, Tarassovi and Ballum) in 595 samples from 60 herds. A brief history was obtained to analyze risk factors for reproductive disorders. A total of 45.9% of the tested horses were seropositive, of which the most frequent serogroups were Icterohaemorrhagiae (Icterohaemorrhagiae and Copenhageni serovars) and Ballum (Ballum serovar). Simple infections were found in 45.4% of seropositive animals, while mixed infections occurred in 54.6% of horses. There was a correlation between seropositivity and age and sex, that is, seropositivity was more frequent in animals over 6 years old and in females. There was no correlation between seropositivity and reproductive disorders. We conclude that there is a high seroprevalence of Leptospira spp. in southern Brazil with predominance of Icterohaemorrhagiae serogroup, mainly in older animals. Location, breeds, contact with dogs or other domestic animals are not risk factors, whereas gender is a risk factor. Reproductive disorders are not due to leptospirosis in the study region.