2.2. Fish and feeding trial
Juvenile red sea bream were transported from a private hatchery to the Marine and Environmental Research Institute of Jeju National University (Jeju, South Korea). The health status of fish was checked upon arrival, and they were quarantine bathed with 100 mg l−1 formalin for 20 min. All the fish were fed the basal diet for 2 weeks to become acclimatized to the experimental conditions and facilities. At the end of the acclimation period, 20 randomly captured fish (averaging at 13.3 ± 0.2 g) were distributed into each polyvinyl circular tanks of 120 L capacity and supplied with sand filtered seawater at a flow rate of 3 L min−1 and aeration to maintain enough dissolved oxygen. Triplicate groups of fish were hand-fed with one of the test diets to apparent satiation twice daily (09:00 and 17:00 h) for 9 weeks. Uneaten food, if any, was siphoned out 30 min after feeding, dried and feed intake was calculated by subtracting the weight of uneaten feed from the amount of total supplied feed. Growth of fish was measured with three-week intervals. Feeding was stopped 24 h prior to weighing or blood sampling to minimize handling stress on fish. The water temperature during the feeding trial ranged from 21 to 27 °C and the photoperiod was maintained on a 12:12 light:dark schedule.