The endocrine regulation of feeding in fish

在所有脊椎动物中，食物摄入量的调节涉及大脑和外周组织产生的食欲调节因子(ARF)的复杂网络。ARF影响大脑中的摄食中心，并刺激或抑制摄食。尽管最近取得了进展，但我们目前对鱼类摄食调节的了解有限，而且基于少数模式物种，例如金鱼。然而，鱼类物种和饮食/摄食习性的多样性表明，在摄食的内分泌调节中存在物种特有的机制。我的研究通过检测几种海水鱼(如金鱼和溜冰鱼)和淡水鱼(即金鱼)的ARF，建立了鱼的摄食控制的全面和交互模型。 我正在进行的研究的长期目标是识别和描述调节鱼类食欲和食物摄入量的分子和生理机制，并研究它们是如何受到营养状况、饮食、环境线索和生殖事件的调节的。到目前为止，我的研究提供了令人信服的新证据，表明这些因素的结构、产生地点和作用机制在种间存在重大差异。我的项目的独特之处在于，它是世界上少数几个使用综合(从整个动物到基因)比较方法来研究淡水和海水鱼类摄食的内分泌调节的项目之一。我们还使用了多种互补技术，包括体内(注射、行为观察)和体外(克隆、qPCR、RNAseq、组织培养、酶分析、原位杂交)方法。 我们的短期目标是：(1)确定温带和热带鱼类ARF的特征，并评估ARF之间的相互作用；(2)检查禁食、饮食和运动对摄食和ARF的影响；(3)检查肠道微生物区系和ARF之间的相互作用；(4)检查环境变化和潜在的气候变化对摄食和ARF的影响；(5)评估ARF在调节摄食和繁殖方面的相互作用。 这项研究将使我们能够建立一个一般模型，阐明鱼和脊椎动物摄食的内分泌调节及其对生长和繁殖的影响，为管理和加强鱼类的生长和繁殖提供新的方法，并了解不同的鱼类物种如何应对具有生态重要性的环境压力因素(例如全球变暖)。我们的结果将是非常有益的，并可能对当地和跨国渔业和水产养殖业产生影响。

In all vertebrates, the regulation of food intake involves intricate networks of appetite-regulating factors (ARFs) produced by both brain and peripheral tissues. ARFs affect feeding centres in the brain, and either stimulate or inhibit feeding. Despite recent advances, our current understanding of the regulation of feeding in fish is limited and based on few model species, e.g. goldfish. However, the diversity in species and diets/feeding habits in fish suggests the existence of speciesspecific mechanisms in the endocrine regulation of feeding. My research has established comprehensive and interactive models of feeding control in fish by examining ARFs in several marine (i.e. cunner and skate) and freshwater (i.e. goldfish, characids) fish. The ongoing long-term goal of my research is to identify and characterize molecules and physiological mechanisms regulating appetite and food intake in fish, and to examine how they are modulated by nutritional status, diet, environmental cues and reproductive events. To date, my research has provided compelling new evidence that major interspecific differences occur in the structure, sites of production and mechanisms of action of these factors. My program is unique in that it is one of the few worldwide to use an integrative (from whole animal to genes) comparative approach to examine the endocrine regulation of feeding in both freshwater and marine fish. We also use a variety of complementary techniques, which include in vivo (injections, behavioral observations) and in vitro (cloning, qPCR, RNAseq, tissue culture, enzyme assays, in situ hybridization) methods. Our short-term objectives are to: (1) characterize ARFs in temperate and tropical fish and assess the interactions between ARFs (2) examine the effects of fasting, diets and exercise on feeding and ARFs; (3) examine the interactions between gut microbiota and ARFs; (4) examine the effects of environmental changes and potential climate changeinduced variations on feeding and ARFs; (5) assess the interactions of ARFs in the regulation of feeding and reproduction. This research will allow us to establish a general model elucidating the endocrine regulation of feeding in fish and vertebrates and its impact on growth and reproduction, provide new approaches to manage and enhance growth and reproduction in fish and to understand how different fish species deal with environmental stressors of ecological importance (e.g. global warming). Our results will be highly beneficial and likely to have impact in the local and multi-national fishing and aquaculture industries.