Abstract
Previously we described the construction and properties of a rapid yeast bioassay stably expressing human estrogen receptor ¿ (hER¿) and yeast enhanced green fluorescent protein (yEGFP), the latter in response to estrogens. In the present study this yeast estrogen assay was validated as a qualitative screening method for the determination of estrogenic activity in animal feed. This validation was performed according to EC Decision 2002/657. Twenty blank animal feed samples, including milk replacers and wet and dry feed samples, were spiked with 17ß-estradiol (E2ß) at 5ngg ¿1 , 17¿-ethynylestradiol (EE2) at 5ngg ¿1 , diethylstilbestrol (DES) at 10ngg ¿1 , zearalenone at 1.25µgg ¿1 or equol at 200µgg ¿1 . All of these blank and low estrogen spiked feed samples fulfilled the CC¿ and CCß criterions, meaning that all 20 blank feed samples gave a signal below the determined decision limit CC¿ and were thus classified as compliant, and at least 19 out of the 20 spiked samples gave a signal above this CC¿ (ß=5%) and were thus classified as suspect. The method was specific and estrogens in feed were stable for up to 98 days. In this study we also present long-term performance data and several examples of estrogens found in the routine screening of animal feed. This is the first successful example of a developed, validated and applied bioassay for the screening of hormonal substances in feed
| Original language | English |
|---|---|
| Pages (from-to) | 556-568 |
| Journal | Food Additives and Contaminants |
| Volume | 23 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2006 |
Keywords
- green fluorescent protein
- flight mass-spectrometry
- in-vitro
- liquid-chromatography
- recombinant assay
- surface waters
- european eels
- calf urine
- expression
- cells
