Physiology of digestion in aquatic animals

胃肠道 (GIT) 的主要功能是为生长和体内平衡提供能量和营养成分。然而，胃肠道也用于鱼类盐度适应的生理学，例如离子调节和氮平衡。这些不同的作用需要胃肠道、鳃和肾脏等不同器官之间的整合，并最终在消化过程中对这些系统产生下游影响。因此，鱼类的生理学主要是通过未喂食的动物的角度来研究的，以消除消化的复杂影响。然而，为了更现实地了解鱼类的生理学（包括消化这一关键行为），我们必须研究其对生理学的影响。因此，我的研究计划的长期目标是使用比较和综合方法全面了解消化对鱼类生理学的影响。我的短期目标是：1）使用两种鱼类（一种是草食性鱼类，一种是杂食性鱼类）在消化过程中机械地表征鱼类生理学，以及从基因表达到整个动物生理学的综合方法。我将研究消化过程中动物范围内协调一致的生理变化，这些变化反映了饮食成分。 2）确定环境如何影响消化生理学，特别是探索盐度的影响。我将研究盐度增加对消化过程中生理的影响，反映特定栖息地的需求。比较和对比食草动物和杂食动物将揭示饮食结构将如何影响这些变化。 3）探索细菌和古菌的去除和改变对鱼类消化过程中生理的功能影响。我将确定微生物如何为鱼类的胃肠道提供饮食和环境依赖的功能。 通过在该提案中比较草食动物和杂食动物，我们可以更好地理解食物消化的生理反应如何依赖于饮食，并为主要基于未喂食的肉食鱼的现有范例提供对比。此外，通过跨生物水平的整合，我们揭示了多个水平的反应，并揭示了消化对整个生理系统的复杂而有影响力的影响。虽然我的课程重点是消化道，但最终我们将考虑胃肠道功能对整个生物体的生理、性能及其在生态系统中响应环境变化的作用的影响。我的工作的影响在于对鱼类生理学知识的贡献，通过在现有范式中添加消化和饮食来修改我们的理解。这项工作适用于从进化到保护的整个生物领域，并可用于制定水产养殖政策和援助。与我的课程相关的项目将为本科生和研究生提供出色的培训。

A primary function of the gastrointestinal tract (GIT) is the provisioning of energy and nutrient building blocks for growth and homeostasis. However, the GIT is also used for physiology underlying salinity adaptations in fishes such as ion regulation and nitrogen balance. These various roles require integration between separate organs including the GIT, gill, and kidney, and ultimately produce downstream consequences for these systems during digestion. Thus, the physiology of fishes is primarily studied through the lens of unfed animals, to remove the complicating impacts of digestion. However, to obtain a more realistic understanding of fish physiology, one that includes the critical act of digestion, we must study its impacts on physiology. Thus, the long-term objective of my research program is to gain a holistic understanding of the impact of digestion on fish physiology using comparative and integrative approaches. My short terms goals are to: 1)mechanistically characterize fish physiology during digestion using two fish species, one an herbivorous fish and one an omnivorous fish, and integrative approaches from gene expression to whole animal physiology. I will examine coordinated animal-wide alterations to physiology during digestion that reflect dietary composition. 2)determine how the environment affects digestive physiology, specifically exploring the impact of salinity. I will study the impact of increased salinity on physiology during digestion, reflecting the demands of specific habitats. Comparing and contrasting herbivores and omnivores will reveal how diet composition will impact these changes. 3)explore the functional impact of removal and alteration of bacteria and archaea on the physiology of fish during digestion. I will determine how microorganisms provide diet and environmentally dependent functionality to the GIT of fish. By comparing herbivores against omnivores in this proposal, we can better understand how physiological responses to the digestion of a meal are dependent on diet and provide contrast for existing paradigms that are primarily based on unfed carnivorous fish. Furthermore, by integrating across biological levels, we expose multiple levels of responses and reveal the complex and influential impacts of digestion across physiological systems. While the focus of my program is on the digestive tract, ultimately we will consider the consequences of GIT function for the physiology of the whole organism, its performance, and its role in the ecosystem in response to environmental change. The impact of my work is in contributions made to fish physiology knowledge, revising our understanding by adding digestion and diet to existing paradigms. This work is applicable across biological fields from evolution to conservation and can be used to establish policies and aide in aquaculture. The projects associated with my program will provide excellent training for undergraduate and graduate students.