engleski

Acanthocephalans, fish intestinal parasites, as bioindicators of water quality in the freshwater ecosystem

Acanthocephala is a phylum of endoparasites hosted by Mandibulata and Gnathostomata, and phylogenetically related to Rotifera. Acanthocephalans lack digestive system, and therefore depend on host micronutrients, which are absorbed from the fish intestine. This especially involves essential metals, as elements of physiological importance, but also toxic elements which are absorbed even more effectively in acanthocephalans than in other commonly used bioindicator organisms, like fish, crustaceans, and bivalves. Thus, novel field Environmental Parasitology investigates linkage between contamination and parasitism, and possible application of acanthocephalans as indicators in environmental risk assessment studies. Estimation of metal exposure in Croatia was conducted in the lowland Sava River, using Pomhorhynchus laevis and Acanthocephalus anguillae hosted by European chub (Squalius cephalus) and in the karst Krka River, using Dentitruncus truttae hosted by brown trout (Salmo trutta). Acanthocephalan prevalence was much higher in fish from Krka than the Sava River and all acanthocephalan species showed higher metal accumulation than intestinal tissue of fish host. Bioconcentration factor (BCF), the ratio of the element concentration in the parasites to that in host gastrointestinal tissue (BCF = C[parasite]/C[host intestine]), confirmed especially effective accumulation of toxic elements in acanthocephalans, like Ag, Cd, and Pb. Presented research confirmed acanthocephalans as valuable biological indicators of the water quality, which should be combined with a set of physical, chemical and biological parameters, and might in the future be correlated with dynamics and diversity of the free-living rotifers in the freshwater ecosystem for the purpose of comprehensive estimation of environmental health.

Environmental Parasitology ; metal exposure ; Dentitruncus truttae ; Pomhorhynchus laevis ; Acanthocephalus anguillae

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