Hafeez Shifali, Sherwani Fauzia A
Fish Physiology and Toxicological Studies, Faculty of Life Sciences, Department of Zoology, Government Degree College Beerwah, College Road Beerwah, Budgam, Kashmir, 193411, Jammu and Kashmir (UT), India.
Faculty of Life Sciences, Department of Zoology, Aligarh Muslim University, Aligarh, 202002, UP, India.
Fish Physiol Biochem. 2025 Jun 4;51(3):108. doi: 10.1007/s10695-025-01521-y.
Under both natural and cultural environments, the increased water salinity may serve as a significant stressor and have a direct impact on fish metabolism. Therefore, this study assesses the impact of salinity stress on a freshwater fish, Clarias batrachus, when exposed to two different salinity levels (30% and 35% seawater) at three time points (24 h, 3 days and 6 days). Histochemical examination of osmoregulatory organs like skin and gills using Alcian Blue (AB, pH 2.5) and Periodic Acid-Schiff (PAS) staining showed that as salinity and exposure time increased, there was a significant decline in mucus cell numbers, percent area occupancy and the size of both acidic and neutral glycoproteins containing mucus cells. PAS staining also revealed significant histological alterations in kidney tissues, indicating the presence of salinity-induced renal stress. Scanning electron microscopy further revealed structural modifications in chloride cells, underscoring their role in physiological adaptation to varying salinity levels. Even though these adaptations point to a compensatory mechanism, the overall results show that C. batrachus suffers negative effects from prolonged exposure to salinity, including impaired tissue integrity and osmoregulatory efficiency. This study gives significant insights into the physiological challenges encountered by freshwater fish under salinity stress, advancing the knowledge of their adaptive capabilities and limitations.
在自然和养殖环境下，水体盐度升高可能成为一个重要的应激源，直接影响鱼类的新陈代谢。因此，本研究评估了盐度胁迫对淡水鱼胡子鲶的影响，该鱼在三个时间点（24小时、3天和6天）暴露于两种不同盐度水平（30%和35%海水）下。使用阿尔辛蓝（AB，pH 2.5）和过碘酸希夫（PAS）染色对皮肤和鳃等渗透调节器官进行组织化学检查，结果显示，随着盐度和暴露时间的增加，黏液细胞数量、所占面积百分比以及含酸性和中性糖蛋白的黏液细胞大小均显著下降。PAS染色还显示肾脏组织存在明显的组织学改变，表明存在盐度诱导的肾脏应激。扫描电子显微镜进一步揭示了氯细胞的结构变化，突出了它们在生理上适应不同盐度水平的作用。尽管这些适应表明存在一种补偿机制，但总体结果表明，长期暴露于盐度环境中，胡子鲶会受到负面影响，包括组织完整性受损和渗透调节效率降低。本研究为淡水鱼在盐度胁迫下所面临的生理挑战提供了重要见解，增进了我们对其适应能力和局限性的认识。
