Wageningen – The misuse of prohormones in animal farming can be proved by using the right investigation methods. This is the conclusion of the thesis written by Jeroen Rijk, who works at RIKILT, part of Wageningen UR. Rijk will be conferred with a PhD at Wageningen University on 3 December 2010.
The European Union has banned the use of growth hormones in animal farming. However, during routine screening on farms, inspection services are occasionally confronted with specimens containing so-called prohormones. Prohormones display little or no direct hormonal activity, but produce hormonal effects once they have been converted inside the body.
The screening methods developed by Rijk are described in his thesis entitled ‘Hormonal effects of prohormones’. The presence of prohormones in animal feed was proved by imitating their conversion in the laboratory. These techniques caused an increase in hormonal activity and a positive result in bioassays used to measure hormonal activity.
Rijk also explored the practical uses of so-called profiling techniques. Comparisons of chemical profiles in urine, or gene expression profiles in the liver, showed vast differences between animals that had been treated with prohormones and those that had not. These differences can be put to swift use in the practical situation to identify cases of prohormone misuse.
The thesis also shows that the new methods can be used to cut back on animal testing. This is because new hormones (or prohormones) can first be evaluated in the laboratory for bioactivity, metabolism and gene expression. This process is currently carried out via animal testing.
For the press:
More information on this press release is available from Jeannette Leenders, jeannette.leenders@wur.nl.
RIKILT- Institute for Food Safety is part of Wageningen University & Research centre.