Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain.
IRTA-SCR; Unitat de CultiusAqüícoles, 43540 Sant Carles de la Rápita, Spain.
Sci Total Environ. 2018 Dec 10;644:1323-1335. doi: 10.1016/j.scitotenv.2018.07.083. Epub 2018 Jul 13.
Knowledge concerning the health and welfare of fish is important to conserve species diversity. Fish mucosal surfaces, and particularly the skin, are of utmost importance to protect the integrity and homeostasis of the body and to prevent skin infections by pathogens. We performed three trials simulating different environmental and anthropogenic challenges: fish capture (air exposure), bacterial infection and fasting, with the aim of evaluating epidermal mucus as a non-invasive target of studies in fish. In this initial approach, we selected three well-known marine species: meagre (Argyrosomus regius), European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) for our study. Mucus viscosity was measured in order to determine its rheological properties, and mucus metabolite (glucose, lactate, protein and cortisol) levels were analysed to establish their suitability as potential biomarkers. Skin mucus appeared as a viscous fluid exhibiting clearly non-Newtonian behaviour, with its viscosity being dependent on shear rate. The highest viscosity (p < 0.05) was observed in sea bream. Mucus metabolites composition responded to the different challenges. In particular, glucose increased significantly due to the air exposure challenge in meagre; and it decreased during food deprivation in sea bream by a half (p < 0.05). In contrast, mucus protein only decreased significantly after pathogenic bacterial infection in sea bass. In addition, mucus lactate immediately reflected changes closely related to an anaerobic condition; whereas cortisol was only modified by air exposure, doubling its mucus concentration (p < 0.05). The data provided herein demonstrate that mucus metabolites can be considered as good non-invasive biomarkers for evaluating fish physiological responses; with the glucose/protein ratio being the most valuable and reliable parameter. Determining these skin mucus metabolites and ratios will be very useful when studying the condition of critically threatened species whose conservation status prohibits the killing of specimens.
关于鱼类健康和福利的知识对于保护物种多样性非常重要。鱼类的黏膜表面，特别是皮肤，对于保护身体的完整性和内环境稳定以及防止病原体引起的皮肤感染至关重要。我们进行了三项模拟不同环境和人为挑战的试验：鱼类捕捞（暴露于空气中）、细菌感染和禁食，旨在评估表皮黏液作为鱼类研究的非侵入性靶标。在本研究中，我们选择了三种著名的海洋物种：真鲷（Argyrosomus regius）、欧洲鲈鱼（Dicentrarchus labrax）和金头鲷（Sparus aurata）。为了确定其流变特性，测量了黏液的黏度，并分析了黏液代谢物（葡萄糖、乳酸、蛋白质和皮质醇）的水平，以确定它们作为潜在生物标志物的适用性。皮肤黏液呈现出一种粘性液体，表现出明显的非牛顿行为，其黏度取决于剪切率。金头鲷的黏度最高（p < 0.05）。黏液代谢物的组成对不同的挑战做出了反应。特别地，由于真鲷暴露于空气中的挑战，葡萄糖显著增加；而在金头鲷禁食期间，其含量下降了一半（p < 0.05）。相比之下，只有在鲈鱼受到致病性细菌感染后，黏液蛋白才显著下降。此外，黏液中的乳酸立即反映了与缺氧密切相关的变化；而皮质醇仅在暴露于空气中时发生变化，使其黏液浓度增加一倍（p < 0.05）。本文提供的数据表明，黏液代谢物可以被视为评估鱼类生理反应的良好非侵入性生物标志物；其中葡萄糖/蛋白质比值是最有价值和可靠的参数。确定这些皮肤黏液代谢物和比值在研究保护状况禁止捕杀标本的极度濒危物种时将非常有用。
