DETECTION OF HALOFUGINONE RESIDUES IN CHICKEN LIVER-TISSUE BY HPLC AND A MONOCLONAL-BASED IMMUNOASSAY

The quinazolinone halofuginone (Hal) is a feed additive used worldwide to prevent coccidiosis in commercial poultry production. The current regulatory method for determining the action level of Hal residues in poultry involves measuring parent Hal in liver tissue by HPLC. That pr ocedure is not amenable to high sample throughput due to a complex and tedious sample preparation scheme. A competitive enzyme-linked immuno sorbent assay (cELISA) that can be used as a screening tool for determ ining Hal in chicken liver tissue is described. The cELISA method was evaluated using standard curves made in both assay buffer and chicken liver extract. The results demonstrated that standard curves made in a ssay buffer could be used for the cELISA. HPLC vs cELISA results were obtained during two studies; the first study used spiked chicken liver tissue, and the second study used both spiked chicken liver tissue an d incurred levels of Hal in chicken liver tissue. There was good agree ment in the results obtained by HPLC and cELISA. However, in most case s the recovery was higher using the cELISA method than with the HPLC m ethod. In addition, the cELISA method does not require the use of orga nic solvents. These data clearly demonstrate that the cELISA method co uld be used as a screening method for the analysis of Hal in chicken l iver tissue.