Tese (Doutorado) - Instituto Oswaldo Cruz, Pós-Graduação em Biodiversidade e Saúde, 2017.

Abstract: Among the species of fish most used in fish farms in the state of Acre, Leporinus macrocephalus has been highlighting due its large productive capacity in captivity. However, infections caused by parasites can affect the production of this species compromising its growth. The objective of this work was to evaluate the helminth fauna of Leporinus macrocephalus of cultivation systems in the municipality of Cruzeiro do Sul, Acre, and parasitic indexes, contributing to the knowledge of the biodiversity of fish helminths from Brazil. During the period from June 2014 to March 2015 two hundred specimens obtained of two fish farms, one semi-intensive system and one extensive system were collected, being 100 fish in each during the dry and rainy seasons, 50 specimens by season. The helminths were fixed and processed for study according to the specific methodology for each group. The prevalence, mean abundance and mean intensity of infection were calculated for each species of parasite. For species that occurred on both cultivation systems and in dry and rainy seasons the prevalences were compared using the Chi-square test (&#9672). The mean abundance and mean intensity of infection were compared by the normal Z approximation by the Mann-Whitney U-test. For the infracommunity in each cultivation system the ecological descriptors were calculated: index richness Margalef (D), diversity Brilloiun, index (H), Evenness (J) and Berger Parker dominance (d). 1,241 helminths of 15 species were colletected: Urocleidoides paradoxus, Urocleidoides eremitus, Tereancistrum parvus, Tereancistrum paranaensis, Jainus leporini, Kritskyia eirasi, Microcotylidae gen. sp., Dactylogyridae gen. sp. 1, Dactylogyridae gen. sp. 2, Dactylogyridae gen. sp. 3, Prosthenhystera obesa, Procamallanus (Spirocamallanus) inopinatus, Rhabdochona (Rhabdochona) acuminata, Goezia leporini, e Brevimulticaecum sp. (larva). Descriptors of parasitism were generally low and varied among species. In extensive fish farm, the highest indexes were for Monogenoidea and semi-intensive for Nematoda. In extensive fish farm there was no variation in the prevalence of infection and three species presented differences in the parasitic indexes between the seasons. In the semi-intensive fish farm there was a higher prevalence of infection in the dry season, and all the parasites presented differences in the indexes between seasons. Although clinical signs of disease was not observed, parasitic data suggest preventive measures in systems, avoiding future epizootic cases, with economic losses in fish farm.

Orientadora Dra Simone Chinicz Cohen