Abstract: Stizostedion lucioperca aquaculture/stoking, remains
a restrained industry due to several factors such as the paucity of freshwater
resources and studies on the physiological responses of this species under
environmental changes. The fish were subjected to handling stress by holding
them out of the water in a hand-held dip net for 30 sec and netting the
fish from the rearing tanks and transferring them to a small confinement
tank. Sufficient aeration was supplied to the confinement tank to revert
additional stress from oxygen depletion. Then measured changes in plasma
cortisol levels and the growth ability (body composition) in Stizostedion lucioperca subjected to handling stress. Blood samples were collected from the fish after exposure to the handling stress. Crude protein (Nx6.25)
was determined according to the Kjeldahl method, moisture content was
determined by oven drying at 105 ± 2 °C to constant weight and
ash by heating in a muffle furnace at 550 °C to constant weight. Total
lipids were extracted according to the Bligh and Dyer method. The results
indicated that, handling stress significantly increased the plasma levels
of cortisol 59.04 ng mL-1 versus 40.83 ng mL-1 in
control group. Also the decrease of the level of protein and lipid concentrations
show a significant difference between treatment and control (p<0.05).
As protein and lipid decreased, moisture increased from 78.19% in control
to 80.40% in treatment groups. According to the results, there was no
significant change in ash content in control and treatment groups which
was about 9%. In other words, it could be emphasized that nutrition-related
behavior of Stizostedion lucioperca resulting from the activation
of the hypothalamic/inter-renal axis in response to stress despite of
different reactions bear resemblance to that of other fishes. Present
data indicate that cortisol appears to be adequate to assess stress in
Stizostedion lucioperca.
Abbasi Fatemeh, Ghafori Sanaz and Jamili Shahla, 2008. Plasma Cortisol Changes and Body Composition in
Stizostedion lucioperca Exposed to Handling Stress. Pakistan Journal of Biological Sciences, 11: 623-627.
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