Parasitic fauna of the siluriform hybrids cachapinta and jundiara in the first stages of development

Abstract

The objective of this work was to evaluate the parasitic fauna of the hybrid fish cachapinta (Pseudoplatystoma corruscans male x P. reticulatum female) and jundiara (Leiarius marmoratus male x P. reticulatum female) at the hatchery stages. A total of 315 animals, 126 hybrids of jundiara and 189 hybrids of cachapinta were examined according to their development stage: larvae, post‑larvae, and fingerlings. Larvae and post‑larvae were pressed between a slide and a cover slip and were observed under optical microscopy. Fingerlings were externally observed in a stereomicroscope and dissected for internal evaluation of organs. Water quality parameters were measured in all cultivation phases. The parasitological exam showed the presence of the protozoa Epistylis sp. and Trichodina sp., on integument and gills, and Ichthyophthirius multifiliis on integument, of the helminth Monogenea on gills, and of digenean metacercariae on gills, spleen, kidneys, liver, and intestines in both hybrid fish evaluated. The parasites Epistylis sp., Trichodina sp., and digenean metacercariae occur most frequently in the two hybrids at the stages of post‑larvae and fingerlings. There is a higher prevalence and diversity of parasites in the fingerling phase of the studied hybrids.