Depletion of lipid, lean, and ash masses in food-restricted American black ducks
| Autor: | Roy L. Kirkpatrick, Thomas H. Eason, John M. Morton, David W. Howerter, Christine M. Long |
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| Rok vydání: | 1994 |
| Předmět: | |
| Zdroj: | Canadian Journal of Zoology. 72:1492-1496 |
| ISSN: | 1480-3283 0008-4301 |
| Popis: | We investigated the rate and order of depletion of lipid depots and other body components in American black ducks (Anas rubripes) responding to food restriction. Forty-one hatching-year ducks were placed on one of four diets to induce high variability in body composition. Regression analyses suggest that for every 1-g decrease in body mass, lipids decreased 0.53 g, water decreased 0.36 g, ash-free nonlipid dry mass (NLDM) decreased 0.05 g, and ash decreased 0.02 g. However, depletion rates were not uniform among lipid sources. Both lipid mass and lipid depletion rate were ranked in descending order: subcutaneous, carcass, omental, and visceral. Despite disproportionately low depletion rates, intraperitoneal depots were depleted before subcutaneous or carcass lipids. We also found evidence of a sexual difference in endogenous nutrient utilization by American black ducks in response to food restriction. Males reduced NLDM (mostly breast muscle), visceral lipids, and subcutaneous lipids concomitantly. In contrast, females did not utilize NLDM but depleted visceral and subcutaneous lipids at rates 146–175% higher than males. These data suggest that relationships between depot and total body lipid masses are not necessarily uniform. Furthermore, it may not be possible to apply some measures of physiological condition equitably to both sexes of Anatinae. |
| Databáze: | OpenAIRE |
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