PATHOLOGY ASSOCIATED WITH Pseudomonas sp. IN Pseudoplatystoma fasciatum

Pseudoplatystoma fasciatum is a native fish from the continental wáter in the Amazonian Región from South America. The objective of the present research was to describe the pathology and identification of the causal agent of Pseudoplatystoma fasciatum mortality in a stuary from the IIAP, located in Pucallpa, Ucayali Region, Peru.

Pseudoplatystoma fasciatum fingerlings 3.5 months old, 15 cm long and 65 g weight average were evaluated clinically in the estuary; hematocrit, and hemoglobin levels were determined. At the necropsy, anatomic changes were evaluated and ascitic fluid from the celomic cavity, gills and natatory bladder inocula were obtained and streaked on blood and Mc Conckey agar and the growth was replicated on TSI and cetrimide agar. Clinically, fish were floating on the water surface showing breathlessness and loss of equilibrium. Hematocrit and hemoglobin levels were 2.8% and 1.8g/dl respectively.

At necropsy, pale color and edema in gills, abdominal bloating containing abundant yellowish bloody fluid in the cavity were found. Peritoneum showed a bloody coloration and edema and the natatory bladder a whitish fluid content. The liver was yellowish and the pancreas whitish-gray, and both showed increased size. In lumen of the intestine, abundant fluid was found.

Using the blood, Mc Conckey, TSI and cetrimide agars, Pseudomonas sp was identified. In conclusion, Pseudoplatistoma fasciatum mortality resulted from a hemolitic anemia and ascitis associated with Pseudomonas sp. infection.