Use of the oligochaete, Lumbriculus variegatus, as a prey organism for toxicant exposure of fish through the diet

Abstract

The oligochaete, Lumbriculus variegatus, has several characteristics that make it desirable as a prey organism for conducting dietary exposure studies with fish. We conducted 21- and 30-d experiments with young fathead minnows (Pimephales promelas) and rainbow trout (Oncorhynchus mykiss), respectively, to determine whether a diet consisting solely of L. variegatus would support normal growth and to compare performance with standard diets (Artemia nauplii, frozen brine shrimp, or trout chow). All diets were readily accepted, and fish survived and grew well. Food conversion in both fathead minnows and rainbow trout was as high as or higher for the oligochaete diet compared with others, although this comparison is influenced by differences in ration, ingestion rate, or both. The oligochaete diet had gross nutritional analysis similar to the other diets, and meets fish nutrition guidelines for protein and essential amino acids. Methodologies and practical considerations for successfully using oligochaetes as an experimental diet are discussed. Considering their ready acceptance by fish, their apparent nutritional sufficiency, the ease of culturing large numbers, and the ease with which they can be loaded with exogenous chemicals, we believe that L. variegatus represents an excellent choice of exposure vector for exposing fish to toxicants via the diet.

Evaluation of Bioaccumulation Using In Vivo Laboratory and Field Studies

“…The second approach involves spiking a test substance into food and then administering this contaminated diet to test organisms at a fixed ration, typically expressed as a fraction of the body wet weight per day, for a specified uptake period (Zitko and Hutzinger 1976; Zitko and Carson 1977; Zitko 1980; Bruggeman et al 1981; Muir and Yarechewski 1988; Opperhuizen and Schrap 1988; Schrap and Opperhuizen 1988; Clark and Mackay 1991; Fisk et al 1996, 1998; Dabrowska et al 1999; Martin et al 2003; Tomy et al 2007). A synthetic diet is typically used, but live prey organisms can also be first exposed to the test substance and then used as the dietary source of exposure (Mount et al 2006). A depuration phase is often included in which a subset of the exposed test animals are fed clean food and periodically sampled for chemical residues.…”

Legacy Contamination from Mercury Mining in the Fergana Valley Region of Central Asia

“…The THg detection limit of the outlined method is 0.005 μg g –1 w.w. of sample . After Hg quantification, wet weight Hg concentrations were converted to dry weight concentrations by dividing wet weight Hg concentrations by the proportion of total sample weight constituted by dry mass, estimated to be 0.2 for earthworms and 0.25 for fish muscle samples which have been frozen and thawed. − These conversions enabled comparisons of dry weight Hg concentrations among all sample types.…”

Testing the Use of Standardized Laboratory Tests to Infer Hg Bioaccumulation in Indigenous Benthic Organisms of Lake Maggiore (NW Italy)

“…The weight of the aliquots of worms were carried out by gently filtering them (−0,8 kPa, 60 s) on a pre-weighed polycarbonate filter (Nuclepore 3.0 µm, 47 mm i.d.) in order to remove the excess water [38].…”