Ensiling as a means of reducing ochratoxin a concentrations in contaminated barley

Abstract

Abstract The feasibility of ensiling barley contaminated with ochratoxin A (OA) as a practical method of inactivating OA was examined in in‐vitro and in‐vivo studies. In the in‐vitro study, OA concentrations in barley decreased by approximately 68% after being ensiled for 56 days. To verify the destruction of the OA, a chick feeding trial was conducted. Samples of a toxin‐and mould‐free barley, mould‐contaminated barley, a barley sample naturally contaminated with OA or a barley with added OA were each divided into two equal portions, one of which was ensiled for a period of 28 days. The mould‐contaminated barley was naturally contaminated with Penicillium cyclopium and Aspergillus flavus . Diets containing either the ensiled or non‐ensiled barley samples were then fed to 7‐day‐old Leghorn chicks for two 7‐day periods. Changes in feed consumption (RFC) and body weight gain (RWG) relative to control birds, feed to gain ratio and mortality were monitored. The OA concentration in the two OA‐containing barley samples decreased by 58% after 28 days of ensiling, but there was no improvement (P >0.05) in chick performance or mortality compared with the non‐ensiled diets. The average RFC values for chicks fed the mould‐ and OA‐containing diets were less than 50% of the controls and RWG generally less than 30%. In absolute terms, chicks fed the ensiled barley diets also performed about 6% poorer (P <0.003) than those given the non‐ensiled barley. Ensiling did not appear to be a practical method of reducing teh toxic effect(s) of OA, despite the apparent decrease in OA concentration. Grain sampkles should be tested for the presence of a toxin prior to ensiling to avoid possible toxin analysis problems later.