A miniaturised method for feeding rate in daphnids - A physiology endpoint for risk assessment

Pollution is monitored in the ecosystem with methods that aim to capture the presence of pollutants. However, risk assessment is more oriented to develop sensitive metrics that rely on Novel Approach Methodologies (NAMs) which can support existing methods and offer mechanistic insight to the action of pollutants. Feeding is a phenotypic endpoint assessed in many organisms to describe changes in their physiology. For daphnids, feeding is usually quantified with assays employing large volumes and long incubation periods or even cumbersome techniques. In this paper we present a more robust and a faster method to assess feeding with simple fluorescence measurements based on the consumption of algae. The optimized protocol has been tested in a range of pollutants and feeding has proved to be a sensitive indicator for non-lethal exposures.