Intestinal obstruction caused by Echinorhynchus sp. (Acanthocephala) in farmed Piaractus mesopotamicus (pacú) in Argentina

EXEQUIEL OSCAR FURLAN; DANA MURIEL ALVEZ; SILVINA BEATRIZ CHEMES; PABLO MARTIN BELDOMENICO; ELIANA HEBERLE

Shanghai

Conferencia; Global Conference on Aquaculture, acuaculture for food and sustainable development; 2021

Organización de las Naciones Unidas para la Agricultura y la Alimentación

The cultivation of pacú (Piaractus mesopotamicus) in Argentina has had a significant increase in the last decade, particularly in the provinces of Misiones, Corrientes, Formosa, Chaco and Santa Fe. Intensive and semi-intensive farming systems used for fish farming cause stress and overcrowding, which may lead to higher risk of pathogen exposure and disease (Sadhu et al., 2014; Henning et al., 2017). Here we studied the community of endoparasites associated with P. mesopotamicus in a closed culture system in the province of Santa Fe, Argentina. Thirty-one pacú specimens sampled in January and February 2021 (standard length 30.39 ± 5.1 cm; average weight 1.08 ± 0.43 kg) were examined by dissecting the entire digestive tract in search of endoparasites. Using staining and conservation techniques, the extracted helminths were fixed and taxonomically identified. All 31 fish were parasitized with acantocephalus of the genus Echinorhynchus, with high infestation intensities (mean±SD: 191.74 ± 63.74). These helminths were located mostly in the proximal portion of the foregut (anterior to the stomach) and in the intestinal cecum, causing obstruction of the intestinal lumen. A species of the genus Echinorhynchus, E. jucundus, was documented in low infestation densities of wild pacu populations (Argentina and Brasil) and in high densities in captivity (Brasil) (Ferraz de Lima et al., 1980). These helminths in high densities can cause severe reactions in the hosts, from inflammations and lacerations, to the penetration of the intestinal wall, causing problems in feeding performance and in extreme cases death. This study constitutes the first record of the genus Echinorhynchus parasitizing P. mesopotamicus under culture conditions in Argentina, taxonomic and molecular studies will be required to confirm this helminth at a specific level, as well as histopathological studies that demonstrate the damage caused by these parasites.