Study of liver, kidney and gill tissue changes of Rainbow trout (Oncorhynchus mykiss) Due to Aquagerm bathing

Aquagerm is an antiseptic and mixed-oxidant disinfectant produced for the first time in Iran with the capability of being used for aquatics. The current study, which was undertaken in February 2009, aims to address the potential tissue Changes in rainbow trout (Oncorhynchus mykiss) if bathed in aquagerm as disinfectant. In this study, 40 fishes in natural and healthy conditions were picked from a fish farm in Mojen village - Shahrood city, 20 of them transferred into the treatment pond, while the others were moved to the control pond. 8 days later, the treatment group were bathed in 1/2000 aquagerm dozap for 45 minutes.Then through 0, 40, 24 and 48 hours. Section 5 sample from treatment group and 1 from control were caught in order to autopsy from kidney , liver and gills. Subsequently, the samples were fixed in 10% formalin. Samples were transferred to the laboratory of Tehran University. In the research lab, through standard methods of histology, 5-micron sectional samples were prepared for optical microscopy. Through microscopic analysis of liver, some evidences of increased melano-macrophage, glomerular shrinkage, and dilatation in Bowman capsules were observed though no tissue damage of any kind was observed in liver. As regards gill microscopy, symptoms such as inflation, detachment of basic layers in secondary gill filaments, aneurysm, appearance of clavate filaments, inflation and disorder in gill septum, shortened and thickened secondary gills, hyperplasic perichondrium, and epithelial lifting were observed. In general, such observed damages, which were in fact natural responses of studied organs to external materials, are not regarded as pathologic damages. All in all, it seems that the application of this specific disinfectant poses no imminent threat to the vital organs of the samples studied here.