Mortalidade em pacus (Piaractus mesopotamicus) ocasionada por Pantoea agglomerans e Pseudomonas aeruginosa em tanque escavado
Ferreira, Milena WolffSantos, Ricardo MartinsSilva, Alanderson Rodrigues daMarino, Elizangela DomenisMakimoto, Sarah SaoryBarbosa, Guilherme Ribeiro CapibaribeAndrade, Gisele Braziliano de
Background: Fish production in Brazil is growing strongly. This growth is being mainly driven by mainland aquaculture,which in 2017 produced 691.700 tons of fish. To improve production levels, fish farms have become increasingly intensive,but in these systems, the high fish densities in the ponds, the high feeding rate, and the high organic matter levels in thewater can lead the fish becoming stressed. This can cause bacterial proliferation and an increase in mortality. Most species of fish-causing bacteria are saprophytes. They are found naturally in the environment and are usually responsible forsecondary or opportunistic infections. This study reports on an outbreak of Pacus (Piaractus mesopotamicus) mortality atan intensive fish farm, in the municipality of Campo Grande, MS, Brazil, that used excavated tanks.Cases: The outbreak occurred at a fish farm in the municipality of Campo Grande, MS, during August, 2015. A total of200 pacus in two tanks died after they showed the following symptoms: lethargy, anorexia, increased mucus production,and disordered swimming and water surface searching. The temperature and dissolved oxygen were measured using adigital thermometer and an oximeter, respectively, and water transparency was measured with a Secchi disc. The pH wasmeasured using a portable digital potentiometer. The values for the water quality parameters analyzed during the mortalityperiod were temperature, 22.5oC; transparency, 20 cm; oxygen dissolved in the early morning 3 mg/L and at the end ofthe afternoon, 4.5 mg/L; pH 8.3; and toxic ammonia, 0.002 ppm. Five fishes were collected from the tank, immediatelycooled to 4°C, and sent to the Microbiology and Pathology Laboratories to perform the microbiological and pathologicallaboratory procedures. After the replication process, the slow glucose fermentation characteristics in MacConkey Agar andother biochemical tests showed that the lactose non-fermenter bacterium was Pseudomonas...(AU)
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