2. Material and methods
2.1. Experimental design and animals
The experimental design was completely randomized with four
replications in a 2 2 factorial design with two stocking densities
(18.75 and 62.50 fish m3
) and two diets (supplemented diet and
control diet). The experimental period was 84 days.
Tilapias (O. niloticus) with an initial average weight of
32.63 ± 1.25 g were distributed into 16 concrete tanks (800 L) and
stocked at two densities: low (18.75 fish m3
) and high
(62 50 fish m3
). A water flow system with a flow rate of 2.5 L min1
and continuous aeration was used. The water temperature was
controlled by an electronic thermostat and heater. The water
quality parameters were measured daily (temperature and dissolved
oxygen) and weekly (pH and total ammonia).
2.