Postexposure Feeding Depression: A New Toxicity Endpoint for Use in Laboratory Studies With Daphnia Magna

Abstract

In situ bioassays with daphnids currently employ lethality as an endpoint, and although sublethal responses (reproduction and feeding rate) can be measured in the field, such endpoints pose major practical challenges. Previous studies have indicated that Daphnia magna exposed to toxic substances can exhibit delayed recovery in feeding behavior (postexposure feeding depression). This simple, robust response has the potential to be an ecologically relevant and potentially diagnostic endpoint. This study developed and tested the use of postexposure feeding depression as a toxicity endpoint in the laboratory environment. First, replicate numbers were manipulated to produce statistically reliable results. Second, postexposure feeding depression in D. magna was studied under laboratory conditions, by employing toxic substances with differing modes of action. Although most substances caused feeding inhibition during direct exposure, not all substances produced postexposure feeding depression. However, the use of lethality as a supplementary endpoint provided an alternative measure when no feeding depression was apparent after exposure. In combination, these endpoints offer a potentially more sensitive, ecologically relevant alternative to the use of lethality alone for in situ bioassay studies.

Modeling responses of Daphnia magna to pesticide pulse exposure under varying food conditions: intrinsic versus apparent sensitivity

“…This assumption corresponds fully with available literature on daphnids and pyrethroids (Day and Kaushik 1987b;Day et al 1987c;McWilliam and Baird 2002;Christensen et al 2005;Reynaldi et al 2006). Due to this effect on assimilation, strong effects were observed on growth curves, which were immediately translated to a delayed onset of reproduction, thereby ultimately affecting the reproduction curves (Fig.…”

Comparison of a test battery for assessing the toxicity of a bleached-kraft pulp mill effluent before and after secondary treatment implementation

“…Pulp mill effluents are composed of several substances among which polycyclic aromatic hydrocarbons (McLeay 1987). In a study on the applicability of a postexposure feeding test with D. magna for toxicity assessments, McWilliam and Baird (2002) found that the polycyclic aromatic hydrocarbon fluoranthene only induced feeding depression during exposure and not during the postexposure feeding period.…”

“…The D. magna postexposure feeding test was based on the methodology developed by McWilliam and Baird (2002). This test was adopted in the present study because pulp mill effluents contain suspended solids and particulates that may influence the feeding rate.…”

Effects of pesticides and antibiotics on penaeid shrimp with special emphases on behavioral and biomarker responses

“…Food is the basic requirement for growth and other physiological functions of the body [22]. Feeding rate has been proposed in several studies as a sensitive indicator of toxic stress in both freshwater and marine species [23][24][25].…”