Ontogeny of Digestion in Altricial Birds

在这项研究中，PI将研究雀形目(栖息)鸟的消化个体发育，这种鸟是特殊的；即新生的鸟孵化时没有羽毛，闭着眼睛，几乎没有独立移动和进食的能力。除了在更高级的(早熟)状态下孵化的家禽外，很少有人关注鸟类消化生理的发育变化。在其他栖息鸟类和早熟的鸡之间，消化的发育变化可能在许多方面不同。对哺乳动物和家禽的类似发育研究具有基本消化生理学及其在医学和动物生产中的应用方面的高级知识。在第一个目标中，PI的问题是“在成年雏鸟中，消化特征，如酶和吸收水平，在正常的生长和发育过程中是如何变化的？”在第二个目标中，PI们问道：“外栖雏鸟的肠道有多灵活？”许多雀形目动物在生命的最初几天以昆虫为食(蛋白质和脂肪含量高，几乎不含淀粉)，但成年后主要食用种子(碳水化合物含量高)。据推测，它们的消化生化会随着饮食的变化而变化，项目二询问发育变化是根据遗传程序固定的，还是部分受到雏鸟饮食的影响。少年派将研究两种常见的鸟类，家雀和斑马雀。在每个物种中，它们将以不同的合成饲料或不同的比率喂养雏鸟，并在雏鸟发育的几个时间点测试其消化功能，直到成年。PI将首次修改和应用一些分子技术来研究鸟类。除了增加有关野生鸟类生理学的宝贵知识外，项目中开发和应用的方法还增加了在更分子水平上研究鸟类消化生理学的科学能力。研究生、博士后学者、本科生和高中生，其中一些来自代表性较低的群体，将接受综合生物学培训，强调从全动物到分子的概念和方法。研究生导师将参加新的威斯康星州科学教学计划，该计划的目的是提高年轻科学家的教学能力。

In this study the PIs will investigate the ontogeny of digestion in passerine (perching) birds, which are altricial; that is, newborns hatch without plumage, eyes closed, and little ability to move and feed indepedndently. There has been little attention on the developmental changes in digestive physiology in birds, except for poultry which hatch in a much more advanced (precocial) state. Developmental changes in digestion will likely differ in many respects between altricial perching birds and precocial chickens. Similar developmental studies on mammals and poultry have advanced knowledge of fundamental digestive physiology and its applications in medicine and animal production. In the first aim the PI's ask "in altricial nestlings, how do digestive features, such as enzyme and absorption levels, change during normal growth and development?" In the second aim the PIs ask "how flexible is the gut of altricial nestlings?" Many passerine species are fed insects (high in protein and fat and nearly starch-free) during the first few days of life, but as adults consume mainly seeds (high in carbohydrate). Presumably their digestive biochemistry changes with the diet change, and Project II asks whether the developmental changes are fixed according to a genetic program or whether they are partly influenced by the diet the nestling eats. The PI's will study two common bird species, the house sparrow and the zebra finch. In each species, they will feed nestlings either different synthetic diets or at different rates, and they will test the nestlings' digestive function at several time points in their development, through adulthood. The PI's will modify and apply some molecular techniques to altricial passerines for the first time. In addition to increasing valuable knowledge about physiology of wild birds, the methods developed and applied in the projects increase the scientific capacity to study avian digestive physiology at a more molecular level. A graduate student, a postdoctoral scholar, and undergraduates and high school students, some from underrepresented groups, will be trained in integrative biology, emphasizing concepts and methods spanning from the whole-animal to the molecular. Mentors of pre-graduate students will participate in the new Wisconsin Program for Scientific Teaching, whose aim is to improve the instructional abilities of young scientists.