Ordóñez-Grande Borja, Guerreiro Pedro M, Sanahuja Ignasi, Fernández-Alacid Laura, Ibarz Antoni
Department of Cell Biology, Physiology and Immunology, University of Barcelona (UB), 08028 Barcelona, Spain.
CCMAR-Centre for Marine Sciences, University of Algarve, 8005-139 Faro, Portugal.
Animals (Basel). 2021 May 28;11(6):1580. doi: 10.3390/ani11061580.
The European sea bass () is a euryhaline marine teleost that can often be found in brackish and freshwater or even in hypersaline environments. Here, we exposed sea bass juveniles to sustained salinity challenges for 15 days, simulating one hypoosmotic (3‰), one isosmotic (12‰) and one hyperosmotic (50‰) environment, in addition to control (35‰). We analyzed parameters of skin mucus exudation and mucus biomarkers, as a minimally invasive tool, and plasma biomarkers. Additionally, Na/K-ATPase activity was measured, as well as the gill mucous cell distribution, type and shape. The volume of exuded mucus increased significantly under all the salinity challenges, increasing by 130% at 50‰ condition. Significantly greater amounts of soluble protein (3.9 ± 0.6 mg at 50‰ vs. 1.1 ± 0.2 mg at 35‰, < 0.05) and lactate (4.0 ± 1.0 µg at 50‰ vs. 1.2 ± 0.3 µg at 35‰, < 0.05) were released, with clear energy expenditure. Gill ATPase activity was significantly higher at the extreme salinities, and the gill mucous cell distribution was rearranged, with more acid and neutral mucin mucous cells at 50‰. Skin mucus osmolality suggested an osmoregulatory function as an ion-trap layer in hypoosmotic conditions, retaining osmosis-related ions. Overall, when sea bass cope with different salinities, the hyperosmotic condition (50‰) demanded more energy than the extreme hypoosmotic condition.
欧洲海鲈（）是一种广盐性海洋硬骨鱼，经常出现在咸淡水和淡水甚至高盐环境中。在此，我们将海鲈幼鱼暴露于持续的盐度挑战中15天，模拟一种低渗（3‰）、一种等渗（12‰）和一种高渗（50‰）环境，此外还有对照（35‰）。我们分析了皮肤黏液分泌和黏液生物标志物的参数，将其作为一种微创工具，以及血浆生物标志物。此外，还测量了钠钾ATP酶活性以及鳃黏液细胞的分布、类型和形状。在所有盐度挑战下，分泌的黏液量均显著增加，在50‰条件下增加了130%。释放出的可溶性蛋白（50‰时为3.9±0.6毫克，35‰时为1.1±0.2毫克，<0.05）和乳酸（50‰时为4.0±1.0微克，35‰时为1.2±0.3微克，<0.05）明显更多，伴有明显的能量消耗。鳃ATP酶活性在极端盐度下显著更高，鳃黏液细胞分布重新排列，在50‰时有更多酸性和中性黏蛋白黏液细胞。皮肤黏液渗透压表明在低渗条件下作为离子捕获层具有渗透调节功能，保留与渗透相关的离子。总体而言，当海鲈应对不同盐度时，高渗条件（50‰）比极端低渗条件需要更多能量。
