Thermoregulation in Florida manatees (Trichechus manatus latirostris) -Understanding the cold-stress syndrome in terms of physiology, morphology and early diagnosis

佛罗里达海牛（Trichechus manatus latirostris）的体温调节——从生理学、形态学和早期诊断角度了解冷应激综合征

• 批准号: 281693982
• 负责人: Dr. Nicola Erdsack
• 金额: --
• 依托单位: Mote Marine Laboratory and Aquarium
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/281693982?language=en
• 关键词: Thermoregulation; Florida; manatees; Trichechus; manatus

The Florida manatee (Trichechus manatus latirostris) belongs to the sea cows or Sirenia, a group of fully aquatic mammals consisting of four recent species. As the only herbivorous marine mammals, sireneans live in tropical/subtropical habitats and are adapted to high water temperatures. Particularly the Florida manatees are extremely sensible to lower water temperatures. One of the major threats to this species is the so called cold-stress syndrome (CSS), occurring in manatees that are exposed to water temperatures <20°. In particular subadult animals are affected by CSS, failing to find the way to warm water refugees (warm fresh water springs, warm-water discharges from power plants) in time, when water temperatures decrease. Amongst others, CSS symptoms are immune suppression, organ failure, lesions of heart, skin and other organs, eventually causing the death of the animal. The proposed project comprises three major objectives: (a) The identification of indicators for early recognition of cold stress in a manatee prior to the appearance of life-threatening CSS symptoms. (b) The identification of environmental, physiological and morphological parameters influencing the susceptibility to thermal stress in Florida manatees on the basis of early-diagnosed animals (see (a)) as well as animals with CSS symptoms. (c) Based on (a), (b) and additional morphological studies in deceased animals, to generate well substantiated hypotheses on the physiological causation of CSS in manatees. My hypotheses are: (1) Incipient cold-stress can be recognized by changes in surface temperature of body parts above the water surface via infrared-thermography (IRT), in particular the open nostrils while breathing at the surface. (2) The amount and composition of biofouling on the skin are indicators for the susceptibility of a manatee to CSS. In this context also the role of the skin surface structure for biofouling will be investigated. By means of IRT and further non-invasive methods, an array of measurements, such as skin and core body temperature, heat flux and blubber thickness, will be conducted in manatees suffering from CSS, as well as comparatively in healthy animals. Amount and composition of biofouling on the skin as well as skin surface structure will be documented and analyzed. Histological postmortem examinations will provide further information concerning CSS susceptibility. In particular blubber thickness and composition, skin surface structure, and the presence or absence of arteriovenous anastomoses (AVAs), which are important structures for the regulation of peripheral heat loss, will be examined. This long-term study will lay a foundation to understanding manatee thermoregulation, in particular concerning thermal stress, with possible implications for other mammalian species as well.

佛罗里达海牛 (Trichechus manatus latirostris) 属于海牛或海牛属，这是一组由四个新物种组成的完全水生哺乳动物。作为唯一的草食性海洋哺乳动物，海牛类生活在热带/亚热带栖息地，适应高水温。特别是佛罗里达海牛对较低的水温极为敏感。该物种面临的主要威胁之一是所谓的冷应激综合症 (CSS)，这种疾病发生在暴露于水温 <20° 的海牛身上。特别是亚成年动物会受到 CSS 的影响，当水温降低时，它们无法及时找到温暖的水难民（温暖的淡水泉、发电厂排出的温水）。其中，CSS症状包括免疫抑制、器官衰竭、心脏、皮肤和其他器官病变，最终导致动物死亡。拟议项目包括三个主要目标： (a) 确定指标，以便在海牛出现危及生命的 CSS 症状之前及早识别冷应激。 (b) 根据早期诊断的动物（见（a））以及具有 CSS 症状的动物，确定影响佛罗里达海牛对热应激敏感性的环境、生理和形态参数。 (c) 根据 (a)、(b) 和对死亡动物的其他形态学研究，对海牛 CSS 的生理原因提出经过充分证实的假设。我的假设是：（1）早期的冷应激可以通过红外热成像（IRT）通过水面以上身体部位的表面温度变化来识别，特别是在水面呼吸时张开的鼻孔。 (2) 皮肤上生物污垢的数量和成分是海牛对 CSS 易感性的指标。在这种情况下，还将研究皮肤表面结构对生物污垢的作用。通过IRT和其他非侵入性方法，将对患有CSS的海牛以及健康动物进行一系列测量，例如皮肤和核心体温、热通量和脂肪厚度。皮肤上生物污垢的数量和成分以及皮肤表面结构将被记录和分析。组织学尸检将提供有关 CSS 易感性的进一步信息。特别是鲸脂厚度和成分、皮肤表面结构以及动静脉吻合（AVA）的存在与否，这些都是调节外周热量损失的重要结构。这项长期研究将为了解海牛的体温调节奠定基础，特别是在热应激方面，也可能对其他哺乳动物物种产生影响。

项目成果

Heat flux in manatees: an individual matter and a novel approach to assess and monitor the thermal state of Florida manatees (Trichechus manatus latirostris)

海牛的热通量：评估和监测佛罗里达海牛（Trichechus manatus latirostris）热状态的个体问题和新方法

• DOI: 10.1007/s00360-018-1152-7
• 发表时间: 2018
• 期刊: Journal of Comparative Physiology B
• 作者: Erdsack N;McCully Phillips S. R;Rommel S. A;Pabst D. A;McLellan W. A;Reynolds J. E. III
• 通讯作者: Reynolds J. E. III