Materials and methods
The present study was conducted at the Aquaria Research Unit of Fisheries Faculty of
Mustafa Kemal University, Hatay, Turkey from May 1, 2004 to June 30, 2004. Common
carp (C. carpio) fingerlings were obtained from a local fish hatchery and acclimatised to the
laboratory conditions in fibreglass tank (1000 L capacity) upon arrival. After 15-day
adaptation period, 200 fishes were selected randomly and assigned to the five groups with
four replicates, each had 10 fishes weighing 18.65 0.10 g per fish. Each diet was fed to
fish at the visible satiation per day (at 9:00 and 17:00 h) for 60 days. The aquaria system
was housed inside an experimental room with natural photoperiod (12 h light and 12 h
dark) and each aquarium, had a 96-L water volume capacity, was supplied with continuous
air pumping. A static water system was used, and 80% of the water in each aquarium was