Heat increment of feeding and thermal substitution in mallard ducks feeding voluntarily on grain

摘要: The heat increment of feeding (HIF), including from digestion, assimilation, and nutrient interconversion, may substitute for thermogenesis reduce thermoregulation costs. HIF its substitution have been measured mainly in animals fed single large meals with high protein content, but many species such as some dabbling ducks (Anatini) feed more continuously intermittent small low content. We seven mallard (Anas platyrhynchos) eating mixed grain (corn, wheat, milo) ad libitum while floating on water at 23 °C (thermoneutral) 8 °C. was calculated the difference oxygen consumption between fasted birds, correcting costs behavior, storage (change body temperature), heating food. Substitution occurred if lower 8 °C than 23 °C. Food intake mallards averaged 83% that required maintenance (zero energy balance) 23 °C, 68% Mean (±1 SE) 1.59±0.61 l O2 1.48±0.68 l These values were 4.9% 3.9% metabolizable intake, consistent expected grain. did not differ temperatures (ANCOVA, birds blocks, covariate, P=0.51), indicating no measurable these levels meals. For low-protein foods meals, ecological importance appears negligible during periods when food is below balance.