Departamento de Fisiologia e Farmacologia, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil.
Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
Fish Physiol Biochem. 2012 Aug;38(4):1001-1017. doi: 10.1007/s10695-011-9585-x. Epub 2011 Dec 11.
This study investigated the relationship between ion levels (Na⁺, Cl⁻, K⁺, Ca²⁺, and Mg²⁺) in the fluid phase and total chyme of the contents of the gastrointestinal tract segments of freshwater and marine-estuarine teleosts collected in different salinities (0-34 ppt) in estuarine and freshwater portions of the São Gonçalo channel, southern Brazil. In addition, the relative contribution of feeding and osmoregulation to the ionic content of each portion of the gastrointestinal tract of fishes collected in different ambient salinities was analyzed. There was no relationship between salinity and ion levels in the fluid phase and total chyme of the segments of the gastrointestinal tract when considering all species together. However, there was a significant positive relationship between salinity and ion levels in the fluid phase and total chyme of two fish species (Micropogonias furnieri and Genidens barbus) collected in three or more different salinities. In most species, ion levels in the fluid phase and total chyme changed throughout the gastrointestinal tract, suggesting absorption, but the ionoregulatory mechanisms of the gastrointestinal tract seem to vary according to species.
本研究调查了在巴西南部圣贡萨洛海峡的河口和淡水部分，于不同盐度（0-34 ppt）下采集的淡水和海/河口硬骨鱼类的胃肠道各段内容物的流体相和总食糜中的离子水平（Na⁺、Cl⁻、K⁺、Ca²⁺和 Mg²⁺）与总食糜中的离子水平之间的关系。此外，还分析了在不同环境盐度下采集的鱼类的胃肠道各部分的离子含量中，摄食和渗透压调节的相对贡献。当考虑所有物种时，盐度与胃肠道各段的流体相和总食糜中的离子水平之间没有关系。然而，在 3 种或更多不同盐度下采集的两种鱼类（Micropogonias furnieri 和 Genidens barbus）的流体相和总食糜中的离子水平与盐度之间存在显著正相关关系。在大多数物种中，流体相和总食糜中的离子水平在整个胃肠道中发生变化，表明存在吸收，但胃肠道的离子调节机制似乎因物种而异。
