Histopathological alteration induced in gill tissue of rainbow trout (Oncorhynchus mykiss) treated via gamma-irradiated Ichthyophthirius multifiliis trophonts and coated with alginate nanoparticles

The Ichthyophthirius multifiliis is one of the most important protozoan pathogens of farmed and wild fish populations. In this study, histopathological effects of gamma-irradiated trophonts of I. multifiliis coated with alginate nanoparticles in rainbow trout gill were evaluated. Therefore, after adaption period the fish with mean weight 30 g were distributed to 4 groups: Two groups were treated with gamma-irradiated trophonts of I. multifiliis and coated with alginate nanoparticles, gamma-irradiated trophonts of I. multifiliis. One group was infected with active trophonts of parasite as positive control. In negative control group, no treatment was used. On day 30, gill tissue from treated, infected and control fish was analyzed for evaluating the histopathological alterations. The results showed that the use of alginate nanoparticles formulated in gamma-irradiated I. multifilis trophonts can significantly decrease severe hyperplasia, sub-epithelial edema, and fusion of the secondary lamellae, focal and multifocal necrosi in gill. Also, gamma-irradiated trophonts of I. multifiliis coated with alginate nanoparticles induced an increase in amount of the gill macrophages in treated fish. Therefore, the alginate nanoparticles can be in leading development of safe and efficient gamma-irraditad trophonts deliver tool in rainbow trout with more useful behavior and fewer side effects on gill tissue.