Utilização de um método ex vivo para avaliação do impacto de micotoxinas e eficácia de aditivos antimicotoxinas em suínos

Abstract

The objective of this thesis was to evaluate the impact of aflatoxin B1 (AFB1) and fumonisin B1 (FB1), as well as the efficacy of antimicotoxin additives (AMAs) in pigs, using an ex vivo methodology compared to in vitro and in vivo methodologies. The first study assessed the mycotoxins AFB1 and FB1 and four AMAs using in vitro and ex vivo methodologies. In the ex vivo methodology, four trials were conducted with two treatments, each with 12 repetitions (24 jejunal explants used per trial), using Ussing Chamber (UC) systems: two trials to evaluate two AMAs for AFB1 and two trials to evaluate two AMAs for FB1. The treatments for the two AFB1 trials were: control [buffer solution (BS) + 1 mg/l AFB1] and AMA (BS + 1 mg/l AFB1 + 0.5% AMA 1 or 2). The treatments for the FB1 trials were: control (BS + 50 mg/l FB1) and AMA (BS + 50 mg/l FB1 + 0.5% AMA 3 or 4). The efficacy of the four additives was also tested in vitro. The concentrations of AFB1 in the explants with AMAs 1 and 2 were lower (P < 0.0001) than in the control. AMAs 1 and 2 reduced jejunal absorption of AFB1 by 83.4% and 72.9%, respectively. The explants with AMAs 3 and 4 had lower FB1 concentrations (P < 0.0001) compared to the control. AMAs 3 and 4 reduced FB1 absorption by 31.9% and 17.6%, respectively. In the in vitro test, AMAs 1 and 2 provided 98.4% and 86.3% adsorption of AFB1, respectively, while AMAs 3 and 4 provided 91.2% and 80.5% adsorption of FB1, respectively. The second study was conducted to evaluate the effects of FB1 on the jejunum of pigs using the same ex vivo methodology conducted in parallel with an in vivo trial. For the in vivo trial, 12 male pigs aged 28 to 70 days were subjected to two treatments with six animals each: a control group, fed a basal diet (BD), and the FB1 group, fed BD + 50 mg/kg of FB1. An additional four male pigs from the control group of the in vivo trial were slaughtered for the ex vivo methodology. Thus, in the ex vivo methodology, 16 intestinal explants (4 from each pig) were subjected to two treatments, with 8 explants each, using a UC system: the control group, exposed to buffer solution (BS), and the FB1 group, exposed to BS + 50 mg/L of FB1. Samples from both in vivo and ex vivo models were analyzed for histopathological parameters and subjective intestinal evaluations. The FB1 group showed lower villus height than the control group both in vivo and ex vivo (P < 0.05). A decrease (P < 0.05) in the number of villi, crypt depth, enterocyte height, and enterocyte nucleus size were also observed in the ex vivo FB1 group, with a higher severity score for lymphatic vessel dilation than in the control group (P = 0.0459). The FB1 group also tended to increase the count of goblet cells (P = 0.0736) ex vivo, as well as decrease crypt width (P = 0.0638) in vivo. Therefore, it is concluded that the ex vivo model can be a useful tool in evaluating the efficacy of AMAs for AFB1 and FB1 in pigs. Furthermore, the second study revealed that the ex vivo model showed histopathological lesions similar to those observed in vivo, demonstrating its potential as an alternative approach to assess the effects of mycotoxins in a reduced number of animals.