An improved microtitre enzyme immunoassay to measure the boar taint steroid 5α-androst-16-en-3-one in blood plasma of pigs

Androstenone (5α-androst-16-en-3-one) is a volatile steroid which is synthesized in boar testes and stored in high amounts in fat thus leading to an urine-like odor in pork. Whereas microtiter assays (MTA) exist for fat determination, measurement in blood with MTA was not yet possible. The system reported here is based on a specific antiserum and a horse radish peroxidase conjugate as tracer. For coating bovine serum albumin was avoided which otherwise would lead to unspecific binding. Blood plasma was extracted with n-hexane, solvent was evaporated in a vacuum centrifuge and the extract was taken up in buffer with 10% methanol. Assay sensitivity was 2.5 pg/well (0.025 ng/mL), specificity was confirmed by GC–MS (r = 0.96; n = 50) and inter- and intraassay variation were 4.9% and 5.9%, respectively. Thus an assay system is available for studies in pig production and in wildlife research due to pheromone activity also in other species.