Tissue distribution of ochratoxin A as determined by HPLC and ELISA and histopathological effects in chickens

Ochratoxin A is a common feed contaminant, which may impair animal health and may lead to residues in edible tissues of slaughter animals. To simulate field conditions, broiler chicks were exposed to a total of 0.5 mg ochratoxin A per week for each of 4 weeks. Plasma toxin levels and tissue residues were measured by high-performance liquid chromatography (HPLC) and microplate enzyme-linked immunosorbent assay (ELISA). Results indicate an accumulation in plasma and wide distribution into all organs, with high levels in the liver and the kidney. Microscopical changes that could primarily be associated with toxin exposure were glomerulonephrosis, tubulonephrosis, focal tubular epithelial cell proliferation and multiple, adenoma-like structures in the renal parenchyma. The HPLC and ELISA methods gave similar results for both tissue distribution and depletion. Differences in absolute tissue toxin concentrations obtained by the two methods might be attributed to the different extraction and clean-up procedures, along with antibody specificity. The findings indicate that the dose applied causes subclinical tissue lesions and measurable tissue residues.