Meeting Abstract

45.1  Sunday, Jan. 5 10:15  Compensatory growth and lipid generation in “Threespine Stickleback” (Gasterosteus aculeatus) REYES, ML*; BAKER, J; FOSTER, S; Clark University mreyes@clarku.edu

Many organisms exhibit compensatory growth (CG), an accelerated growth rate during recovery from a total or partial food deprivation than during periods of continuous food availability. However, many aspects of compensatory growth are still poorly understood, such as how compensatory growth potential may change during the life of the organism. We studied compensatory growth in a model organism, the threespine stickleback (Gasterosteus aculeatus), with one objective being to analyze the potential for, and impact of, CG in threespine sticklebacks across their first few months of life, a period corresponding to their first growing season. We hypothesized that fish exposed to a diet deficit in the second month of life, and then returned to an optimal diet, would take longer to achieve a normal growth trajectory than would sticklebacks exposed to diet deprivation in the third and fourth months of life. A second objective was to assess if body lipid content was related to compensatory growth. Our hypothesis here was that stickleback exposed to a diet deficit during earlier stages would fail to recover adequate energy storage reserves. Recent CG models suggest that appetite is regulated in accordance to maintaining a ratio of reserve to body lipid levels. Contrary to our above mentioned hypotheses, our results show that upon comparison with young fish continuously fed an ad libitum diet, one and two month old fish exposed to a diet deficit are better able to regain optimal growth trajectories and regenerate lipids than populations exposed to food deprivation at three months of age.