A 42-d feeding experiment was carried out in the experimental hatchery
of the College of Aquaculture and Fisheries, Can Tho University, Vietnam.
The experiment was set up as a completely randomized design with three
replicates per treatment in 100-L plastic tanks containing 80 L of slightly
brackish water (salinity = 5 ppt) provided with soft continuous aeration.
Water temperature varied between 27 and 28.9◦C over the experimental
period. Juvenile monosex male Nile tilapia were purchased from a reliable
provider in Bac Lieu province and visually checked for signs of disease and
parasites. Before starting the experiment, fish were held in a 1 m3 tank for
1 week for acclimation to laboratory conditions and feeding method (on a
feeding tray for the dual purpose of measuring feed consumption and reducing
water-quality issues). After acclimation, 50 uniformly sized monosex male
Nile tilapia juveniles of individual weight 0.33 ± 0.06 g were stocked in each
tank. Fish were fed twice a day at 7:00 and 17:00 h to satiation. About 1.5 h
after feeding, unconsumed feed was removed carefully by siphoning, transferred
to aluminium cups, and dried to a constant weight. Every day, about
30% of the volume of the water of each tank was exchanged.