Centre for Behaviour and Evolution, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
Proc Biol Sci. 2018 May 30;285(1879). doi: 10.1098/rspb.2018.0417.
In birds little is known about the hormonal signals that communicate nutritional state to the brain and regulate appetitive behaviours. In mammals, the peptide hormones ghrelin and leptin elevate and inhibit consumption and food hoarding, respectively. But in birds, administration of both ghrelin and leptin inhibit food consumption. The role of these hormones in the regulation of food hoarding in avian species has not been examined. To investigate this, we injected wild caught coal tits () with leptin, high-dose ghrelin, low-dose ghrelin and a saline control in the laboratory. We then measured food hoarding and mass gain, as a proxy of food consumption, every 20 min for 2 h post-injection. Both high-dose ghrelin and leptin injections significantly reduced hoarding and mass gain compared with controls. Our results provide the first evidence that hoarding behaviour can be reduced by both leptin and ghrelin in a wild bird. These findings add to evidence that the hormonal control of food consumption and hoarding in avian species differs from that in mammals. Food hoarding and consumptive behaviours consistently show the same response to peripheral signals of nutritional state, suggesting that the hormonal regulation of food hoarding has evolved from the consumption regulatory system.
在鸟类中，人们对向大脑传达营养状态并调节食欲行为的激素信号知之甚少。在哺乳动物中，肽类激素胃饥饿素和瘦素分别升高和抑制摄食和食物囤积。但在鸟类中，胃饥饿素和瘦素的给药均抑制食物摄入。这些激素在调节鸟类物种的食物囤积中的作用尚未被研究。为了研究这一点，我们在实验室中给野生捕获的煤山雀 () 注射了瘦素、高剂量胃饥饿素、低剂量胃饥饿素和盐水对照。然后，我们每 20 分钟测量一次食物囤积和体重增加，作为食物摄入的替代指标，注射后 2 小时。与对照组相比，高剂量胃饥饿素和瘦素注射均显著减少了囤积和体重增加。我们的结果首次提供了证据表明，瘦素和胃饥饿素都可以减少野生鸟类的囤积行为。这些发现增加了证据表明，鸟类物种的食物消耗和囤积的激素控制与哺乳动物不同。食物囤积和消耗行为对营养状态的外周信号始终表现出相同的反应，这表明食物囤积的激素调节是从消耗调节系统进化而来的。
