Bentonite binders in the presence of mycotoxins: Results of in vitro preliminary tests and an in vivo broiler trial

The use of two bentonites differing in composition as potential binders of three mycotoxins present in broiler diets was examined with both an in vitro preliminary test and an in vivo trial. In the in vitro test, the adsorbing and desorbing ability of the two bentonites added at 1% was investigated. Concentrations of aflatoxin B1 (AFB1), ochratoxin A (OTA) and zearalenone (ZEA) were determined with LC–MS/MS and were 0.02 ppm, 0.1 ppm and 2 ppm respectively. In the in vivo trial, a total of 300 day-old, as hatched, broilers were randomly distributed in five dietary treatments with four replicate pens per treatment. In T1 treatment, broilers were fed a basal diet with neither mycotoxins nor bentonite added; in T2 broilers were fed the same diet with 1% m/m bentonite A added. In T3, broilers were fed the same diet with 1% m/m bentonite A added and three mycotoxins (AFB1, OTA and ZEA) added at levels not exceeding the EU maximum. In T4 treatment, broilers were fed the same diet with 1% m/m of bentonite B added and in T5 broilers were fed the same diet with 1% m/m of bentonite B added and mycotoxins at the same levels. Broiler performance and several biochemical and hematological parameters were examined. The in vitro test indicated a complete adsorption of 0.02 ppm AFB1 by both bentonites, present at 1%. No desorption was observed for AFB1. Adsorption and desorption of ZEA and OTA were low. The in vivo trial revealed that the overall performance of broilers did not differ between treatments. Aspartate aminotransferase was found lower in broilers fed mycotoxin contaminated diets but within normal range. The study revealed that the examined bentonites may maintain optimum broiler performance when mycotoxin levels present in the diet do not exceed EU limits and guidance values possibly by ameliorating the negative effects of other mycotoxins, not regulated by EU, present at the same time in the diet.