Nile tilapia fry produced at our laboratory that had been reared to juveniles on commercial diets were acclimated to the experimental basal diet for 2 weeks prior to stocking.
At the end of the acclimation period, fish (average weight of 7.16± 0.18 g) were randomly stocked into 27, 110-L aquaria at 35 fish per aquarium. Aquaria were supplied with flow-through dechlorinated, heated city water at an initial rate of about 0.6 L/min and increased gradually to about 1.0 L/min prior to the end of the study. Water was continuously aerated using air stones.
Water temperature and dissolved oxygen in three randomly chosen aquaria were measured once daily in the morning, using a YSI model58 Oxygen Meter.
During the trial, water temperature averaged 27.9± 0.2 °C, and dissolved oxygen averaged 5.1± 0.1 mg/L. Photoperiod was maintained at a 12:12 h light:dark schedule.