The experimental design and procedures were approved by the
Institutional Animal Care and Use Committee of Nanjing Agricultural
University (Nanjing, China). Blunt snout bream (M. amblycephala) was
obtained from the Fish Hatchery of Yangzhou (Jiangsu, China). Fish
were reared in an indoor circulatory system for 1 week to accustom to
the experimental conditions by feeding a commercial diet prior to the
experiment. After the acclimation, fish of similar sizes (initial average
weight, 11.61 ± 0.05 g) were randomly distributed into 8 flowthrough
rectangular aquariums (155 L each) with 30 fish per tank.
Fish in each aquarium were randomly assigned to one of two experimental
diets. Each diet was tested in four replicates. Fish were handfed
to apparent satiation three times daily (07:00, 12:00 and 17:00 h)
for sixweeks. A 12:12 h light:dark regime (07:00–19:00 h, light period)
wasmaintained by timed fluorescent lighting.Water temperature varied
from 25 to 28 °C, and pH fluctuated between 7.0 and 7.5. Dissolved oxygen
was maintained above 5.00 mg/L during the feeding trial. Total ammonia
nitrogen and nitrite nitrogen were maintained below 0.4 mg/L
and 0.064 mg/L, respectively.