Effects of Acute and Chronic Air Exposure on Growth and Stress Response of Juvenile Olive Flounder, Paralichthys olivaceus

Özet

We studied the effects of acute and chronic exposure to air on the growth and stress response of juvenile olive flounder,Paralichthys olivaceus. To study the stress response, the water was completely drained from the experimental tank, and thestressed group was exposed to air for 5 minutes, after which the tank was refilled with water. This stress was repeated dailyfor 30 days (between 1200 and 1300 h). From day 31 to day 69, no stress was applied. On day 70, the fish were again exposedto the air. The non-stressed group was not subjected to air exposure during the 70 days. We measured cortisol, glucose andlactic acid levels, osmolality, growth, survival, and feeding responses during the 70-day test period. Our results showed thatolive flounder exhibit “typical” physiological responses (in cortisol, glucose, and lactic acid levels and osmolality) to the acutestress induced by air exposure. The response to chronic stress showed a similar increasing tendency. However, theincremental rate of increase decreased as the stress continued. Adverse stress effects, in terms of growth, survival, andresponse to food, were higher in the stressed than the non-stressed group. The effects of chronic stress from air exposureremained for 20 days after the stressor was terminated. These results will help to minimize stress from aquaculture activitiesin olive flounder farm.