title: Fighting fish parasites with photodynamically active chlorophyllin.
abstract: Water-soluble chlorophyll (chlorophyllin) was used in a phototoxic reaction against a number of fish ectoparasites such as Ichtyobodo, Dactylogyrus, Trichodina, and Argulus. Chlorophyllin is applied to the water at concentrations of several micrograms per milliliter for a predefined incubation time, and afterwards, the parasites are exposed to simulated solar radiation. Application in the dark caused only little damage to the parasites; likewise, light exposure without the addition of the photosensitizer was ineffective. In Ichthyobodo, 2 μg/mL proved sufficient with subsequent simulated solar radiation to almost quantitatively kill the parasites, while in Dactylogyrus, a concentration of about 6 μg/mL was necessary. The LD50 value for this parasite was 1.02 μg/mL. Trichodina could be almost completely eliminated at 2 μg/mL. Only in the parasitic crustacean Argulus, no killing could be achieved by a photodynamic reaction using chlorophyllin. Chlorophyllin is non-toxic, biodegradable, and can be produced at low cost. Therefore, we propose that chlorophyllin (or other photodynamic substances) are a possible effective countermeasure against several ectoparasites in ponds and aquaculture since chemical remedies are either forbidden and/or ineffective.
authors.affiliation: Department of Biology, Cell Biology, FAU, Neue Straße 9, Möhrendorf, Germany. donat@dphaeder.de.
authors.forename: D-P
authors.initials: DP
authors.lastname: Häder
authors.affiliation: Developmental Biology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Schmidl
authors.affiliation: Zoological Institute, University Stuttgart-Hohenheim, Stuttgart, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Hilbig
authors.affiliation: Bavarian State Research Centre for Agriculture, Institute for Fisheries, Starnberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Oberle
authors.affiliation: Bavarian State Research Centre for Agriculture, Institute for Fisheries, Starnberg, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Wedekind
authors.affiliation: Department of Biology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Richter
mesh_terms: D000818:Animals; D000977:Antiparasitic Agents / Q000627:therapeutic use*; D017756:Aquaculture; D033341:Arguloida / Q000187:drug effects; D002734:Chlorophyll; D002735:Chlorophyllides / Q000627:therapeutic use*; D016798:Ciliophora / Q000187:drug effects; D005393:Fish Diseases / Q000469:parasitology* / Q000628:therapy*; D005399:Fishes / Q000469:parasitology; D010271:Parasites / Q000187:drug effects*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D010986:Platyhelminths / Q000187:drug effects; D013149:Spiroplasma / Q000187:drug effects; D014867:Water
chemical_list: D000977:Antiparasitic Agents; D002735:Chlorophyllides; D017319:Photosensitizing Agents; D014867:Water; D002734:Chlorophyll; C007020:chlorophyllin
keywords: Aquaculture; Argulus; Chlorophyllin; Dactylogyrus; Ectoparasite; Fish; Ichtyobodo; Parasitology; Photochemistry; Photodynamic reaction; Trichodina