Susceptibilidade de serrasalminídeos e seus híbridos a parasitos em sistema de recirculação indoor e de peixes em policultivo a bactérias

Abstract

Increased susceptibility to parasitic, bacterial and infectious diseases has caused great losses in fish farming. The incidence of parasites and bacteria are a major cause of losses in industrial and sport fish farms. The aquatic environment facilitates the reproduction, dispersal and survival of pathogens. Research on the area of fish health are scarce, especially when regarding native species. The increase in continental aquaculture aroused greater interest of producers and researchers regarding the health aspects in order to improve production techniques. In this context, two studies regarding fish health were conducted. The first study was conducted in order to quantify the parasite load on pacu, tambaqui and pirapitinga, as well as on the hybrids, paqui, pirapicu and Post F1. In the second study, the objective was to isolate and report the incidence of streptococcus and other potential pathogens in polyculture fish farms in Lavras, Minas Gerais, Brazil. For parasitological analysis, we collected gills from representatives of each genetic group, in which we verified two kinds of monogeneans parasites, Anacanthorus sp. and Mymarolhecium sp. We calculated the parametersof prevalence, average intensity, abundance and condition factor. For bacterial identification, random fish samples were collected from seven polyculture fish farms of the micro-region of Lavras, which include the following municipalities: Lavras, Itutinga, Itumirim, Nepomuceno, Carrancas, Sao Sebastiao da Vitoria and Ingai. Specimens of tilapia, dourado, cara, curimba, catfish and piracanjuba were analyzed. Samples of fish organs were collected and seeded in culture medium. After the incubation period, the identification of the microorganisms was conducted according to the traits of the bacterium culture, morphological, and biochemical dyeing. Streptococcus, Aeromonas and Edwardsiella colonies were identified. Bacterial diseases were found only in tilapia, cara and curimba.