Compensatory growth of Nile tilapia (Oreochromis niloticus)

Two feeding trials were conducted, one in a recirculating water system (the first trial) and the other in a fertilized pond (the second trial) to investigate the effects of restricted ration and duration on the subsequent growth of sex-reversed Nile tilapia during the following satiation feeding period. The factorial design consisting of 3 levels of a restricted ration (starvation, 1 % body weight/day and 2 % body weight/day) and 4 levels of a restricted duration (0, 2, 4, 6 weeks) was employed in the first trial in a recirculating water system. Each of 12 treatments (restricted ration level X restricted duration level) with a total period of 12 weeks consisted of two parts, the restricted feeding period and the subsequent satiation feeding period. ANOVA showed that the daily weight gain in the satiation feeding period (DWGs) was significantly affected by the restricted ration levels, but the effect was also influenced by the restricted duration levels. At the levels of starvation and the feeding rate of 1 % body weight/day, restriction for 2, 4 and 6 weeks had the similar DWGs to that of continuous feeding (0 week restriction). At the restricted ration level of 2 % body weight/day, DWGs of restricted feeding for 2, 4, or 6 weeks were significantly higher than that of continuous feeding. Compensatory growth effect occurred at this restricted ration level. Compared with the continuous feeding, the restricted duration of 2, 4 and 6 weeks had better feed utilization. Feeding rate in the satiation feeding period showed a continuous increase as increasing the restricted duration level and reducing the restricted ration level. Approximate analyses of fish carcass in the first trial showed that with the increase of restricted duration level and the decrease of restricted ration level, lipid content decreased greatly. The content of protein and ash, however, mainly affected by the restricted duration.