Research Article: Therapeutic advantages of gamma irradiated propolis in mitigating the risk of Ichthyophthirius multifiliis infection in rainbow trout (Oncorhynchus mykiss)

This study investigated the effects of irradiated-propolis (GI-EEP) supplementation on rainbow trout (Oncorhynchus mykiss) during an Ichthyophthirius multifiliis (Ich) challenge, aiming to determine if it could enhance the fish immune system and improve its response against Ich. In this experiment, ۱۵۰ fish (۳۵.۸۰±۳.۹۵ g) were divided into five groups and fed diets containing gamma-irradiated or non-irradiated propolis extracts or no treatment (control) for ۶۰ days. The fish were then challenged with ۵۰۰۰ I. multifilis theronts per fish. Then, five days post-challenge, blood and skin samples were taken for hematological, biochemical, and gene expression analysis. The results showed that ۰.۵ g kg-۱ of gamma irradiated- ethanol extract propolis (GI-EEP) supplementation regulated electrolyte levels, improved blood biochemical parameters, and enhanced the immune system's response in Ich-infected rainbow trout. It increased lysozyme activity, elevated white blood cell counts, and improved red blood cell counts. Supplementation with GI-EEP positively influenced these parameters, including increasing total protein and albumin and decreasing globulin levels. It also elevated alkaline phosphatase activity, indicating improved inflammation control. Gene expression analysis revealed increased levels of inflammatory and immune response markers, including interleukin ۸, and immunoglobulin M. No significant changes were observed in C۳ complement mRNA gene expression levels. Elevated major histocompatibility complex II mRNA levels indicated an effective immune response. Overall, administering IPE to Ich-infected rainbow trout regulated electrolytes, improved blood parameters, and boosted the immune system's ability to combat the infection. Results showed that the optimal propolis dose for regulating physiological parameters and immune responses in Ich-exposed fish was ۳۰ KGy.

کلیدواژه ها:

Ichthyophthirius multifiliis ، Immune response ، Gene expression ، Hematology ، Blood biochemical parameters ، Rainbow trout