Compensatory growth response in three-spined stickleback in relation to feed-deprivation protocols

Different protocols of food deprivation were used to bring two groups of juvenile three-spined sticklebacks Gasterosteus aculeatus to the same reduced body mass in comparison with a control group fed daily ad libitum. One group experienced 1 week of deprivation then 2 weeks on maintenance rations. The second group experienced 1 week of ad libitum feeding followed by 2 weeks of deprivation. The deprived groups were reduced to a mean mass of c. 80% of controls. The compensatory growth response shown when ad libitum feeding was resumed was independent of the trajectory by which the three-spined sticklebacks had reached the reduced body mass. The compensatory response was sufficient to return the deprived groups to the mass and length trajectories shown by the control group within 4 weeks. There was full compensation for dry mass and total lipid, but incomplete compensation for lipid-free dry mass. Hyperphagia and increased growth efficiency were present in the re-feeding phase, but there was a lag of a week before the hyperphagia was established. The consistency of the compensatory response of immature three-spined sticklebacks provides a potential model system for the analysis and prediction of appetite and growth in teleosts.