Gültepe Nejdet, Ateş Orhan, Hisar Olcay, Beydemir Sükrü
Inebolu Fisheries Faculty, Department of Basic Sciences, Kastamonu University, 37100 Kastamonu, Turkey.
J Aquat Anim Health. 2011 Sep;23(3):134-9. doi: 10.1080/08997659.2011.616848.
Dissolved gas supersaturation is hazardous to fish and can result in gas bubble disease (GBD). Signs of GBD typically include bubbles in the eyes, fins, skin, lateral line, and gill filaments. Ocular abnormalities in diseased salmonids typically occur after aberrant gas production in the eyes. In this study, freshwater rainbow trout Oncorhynchus mykiss were exposed experimentally to percent total gas pressure (TGP%) levels of 104% (control) and 115%. No mortalities occurred during the 7-d experimental period. Effects of GBD were observed externally as a darkened skin, exophthalmia, localized hemorrhage in the eye, and gas bubbles on the operculum. Additional signs included increased swimming activity and, more frequently, panic episodes. Carbonic anhydrase (CA) enzyme activities from the lens and retina were determined at days 0, 1, 3, 5, and 7 of the study. Venous blood gases were also measured on day 7. Retinal pH did not differ between normal and affected fish, but blood characteristics such as the partial pressure of O2, partial pressure of CO2, carboxyhemoglobin level, and bicarbonate ion concentration were significantly elevated in affected fish relative to normal fish. Venous blood pH and oxyhemoglobin levels were not significantly different between affected and normal fish. Patterns of response to total dissolved gas levels differed between the lens and the retina. Mean CA activities in the lenses of fish exposed to a TGP% level of 115% were significantly below those of control fish. However, retinal CA activities did not significantly differ between the two groups over the course of the experiment. These findings show that dissolved gas supersaturation reduces CA activity in the rainbow trout lens.
溶解气体过饱和对鱼类有害，可导致气泡病（GBD）。气泡病的症状通常包括眼睛、鳍、皮肤、侧线和鳃丝出现气泡。患病鲑科鱼类的眼部异常通常在眼睛出现异常气体产生后发生。在本研究中，将淡水虹鳟Oncorhynchus mykiss实验性暴露于总气体压力百分比（TGP%）水平为104%（对照）和115%的环境中。在7天的实验期内未发生死亡。从外部观察到气泡病的影响表现为皮肤变黑、眼球突出、眼部局部出血以及鳃盖上有气泡。其他症状包括游泳活动增加，更常见的是出现恐慌发作。在研究的第0、1、3、5和7天测定晶状体和视网膜中的碳酸酐酶（CA）酶活性。在第7天还测量了静脉血气。正常鱼和患病鱼的视网膜pH没有差异，但与正常鱼相比，患病鱼的血液特征如氧分压、二氧化碳分压、羧基血红蛋白水平和碳酸氢根离子浓度显著升高。患病鱼和正常鱼的静脉血pH和氧合血红蛋白水平没有显著差异。晶状体和视网膜对总溶解气体水平的反应模式不同。暴露于115% TGP%水平的鱼晶状体中的平均CA活性显著低于对照鱼。然而，在实验过程中，两组的视网膜CA活性没有显著差异。这些发现表明，溶解气体过饱和会降低虹鳟晶状体中的CA活性。
