Piaractus mesopotamicus response to persecution stimulus and hypoxia.

Responses to acute stress in pacu (Piaractus mesopotamicus a flat-nosed fish from the Paraguay-Parana River basin) were determined regarding physiological response to adaptation at different blood-sampling times. Experimental design was completely randomised, having 4 treatments 6 x 6 for different times (T15, T30 and T120) and 3 repetitions for control without stress (C). Twenty-one fish weighing 250 ± 2.0 g each (3 Respuesta del Piaractus mesopotamicus a estimulos de persecucion e hipoxia Piaractus mesopotamicus response to persecution stimulus and hypoxia Wilson Gomez-Manrique*1, Haluko Massago2,Daniel Jordan de Abreu Santos 3, Elizabeth CriscuoloUrbinati4 Articulo Original /Original Article Orinoqui 13(2):93-100, 2009 Revista ORINOQUIA Universidad de los Llanos Villavicencio, Meta. Colombia Volumen 13 No 2 Ano 2009 94 fish/aquarium) were used which were randomly distributed in eight 40 L aquariums. Serum glucose (Glu), chloride (Clo) and total proteins (Pro) were evaluated as haematological parameters. Red blood cell (RBC) count, haematocrite (Hto), mean corpuscular volume (MCV) and haemoglobin (Hb) levels were also evaluated. After stress had been produced, plasma glucose significantly increased from 76.41 to 151.22 mg/dL as a response to energy distribution. Chloride response was reduced to 120 min due to the vasodilatation and electrolyte loss to the environment. Blood parameters presented an initial increase followed by later reduction; however, there were no significant difference regarding control. The study showed that pacu presented a tendency to homeostasis for maximum sampling time.