COMPENSATORY GROWTH IN ACIPENSER BAERII, FOLLOWING FEED DEPRIVATION AT HIGH TEMPERATURE: TEMPORAL PATTERNS IN GROWTH, FEED INTAKE AND BODY COMPOSITION

A 7-week study was performed to investigate the compensatory growth responses of Acipenser baerii at high temperature of (29±1)℃. Juvenile Acipenser baerii were starved for 0 (C), 6 (S6), 12 (S12), 18 days (S18) and then re-fed to satiation for 3 weeks. The fish was reared in a recirculating system consisting of 15 tanks (water volume, 300L). During the experiment, photoperiod was 12D:12L with the light period from 08:30 to 20:30, dissolved oxygen was above 6 mg/L, ammonia-N was less than 0.11 mg/L and pH was about 6.8. At the beginning of the experiment, healthy fish initial body weight of (21.61±0.03) g were batch-weighed after 24h feed deprivation and randomly distributed into the 15 tanks (19 fish per tank). During the duration of re-feeding, starved groups were fed to apparent satiation twice daily (9:00 and 15:00). The control group was fed to apparent satiation twice daily (9:00 and 15:00) throughout the experiment. Uneaten feed were collected after 1h in each tank, dried at 60℃ and weighed. Leaching rate of uneaten feed in tanks was estimated by placing weighed feeds into a tank without fish for 1h and then recovering, drying and reweighing. The average leaching rate was used to calibrate the amount of uneaten feed. Weekly changes in specific growth rate, feed intake and body composition were monitored during re-feeding. Three fish samples were collected after starvation at the first week of re-feeding, the second week of re-feeding and the end of the experiment. The S6 and S12 groups could catch up the body weight with that of the control within 1 week of re-feeding which indicated the complete compensation was obtained in the starved fish. However, the body weight of S18 group was still significantly lower than the control at the end of the experiment (P Acipenser baerii at high temperatures which can decline the feed cost and waste pollution but not influence the growth and body composition of fish.