Assessment of estrogenic and thyrogenic activities in fish feeds

► Estrogenic and thyrogenic activities in fish feed extracts were assessed. ► A new stably transfected cell line with the sea bass estrogen receptor was used. ► Estrogenic activity was detected in 11 out of 32 tested pellets. ► A strong activation of the thyroid receptor was caused by 21 of the 32 tested feeds.