2.2. Experimental fish and feeding management
The experiment was conducted in an indoor recirculating aquarium
system(RAS) at the Yangtze River Fisheries Research Institute (Wuhan,
Hubei Province, China). Fish of the GIFT (genetically improved farmed
tilapia) strainwere obtained fromthe Guangxi tilapia national breeding
farm (Nanning, Guangxi Province, China), and were maintained in
a concrete pool (3 × 3 × 5 m) at the experimental base for 2-week
acclimatization. During the acclimatization period, fish were fed the
basal diet in order to adjust to the experimental diet and conditions.
At the beginning of the experiment, the fish were fasted for 24 h
thenwereweighed. Groups of 15 male fish of uniformsize (mean initial
weight = 166.9 ± 1.3 g) were randomly distributed into 21 aquaria
(500 L). The aquaria were connected and running in an independent
RAS. Each experimental diet was assigned to triplicate aquaria and fish
were hand-fed to apparent satiation twice daily for 12 weeks. Experimental
aquaria were provided with continuous flow of circulating