Microarrays

Over the last decade, increasing concern has been raised towards the potential of a diversity of environmental compounds to interfere with the endocrine system of humans and wildlife. Given the ubiquitous presence of these ‘endocrine disrupting chemicals’ (EDCs) in the aquatic environment – often at high concentrations – fish are inevitably exposed, resulting in a variety of adverse biochemical, physiological and reproductive effects, as demonstrated by researchers worldwide.

Until recently, most studies on endocrine disruption have focused on effects at the physiological level. In this research, we will evaluate the effects of endocrine disruption on a lower (gene expression) and a higher (reproductive behaviour) level of biological organization. Adult zebrafish are exposed to (potential) endocrine disruptors under flow-through conditions. After 4 and 28 days, fish are dissected and gonads are collected for the production of oligonucleotide microarrays. Gonadosomatic index (GSI) and vitellogenin of whole body homogenates are determined after 28 days. During every day of the first and the last week of exposure, fecundity and fertility are evaluated. Hatching is followed up until 4 days post-hatch. On day 4, 14 and 28, reproductive behaviour of 10 zebrafish (5 males and 5 females) in the control and high dose group is recorded at 3 time points, using a 3D-behaviour analysis system. Swimming velocity, swimming height and inter-individual interactions are calculated.