Effects of killed Aeromonas hydrophila by heat, formalin, and UV on Liver enzymes, Biochemical factors, and gene expression in rainbow trout, Oncorhynchus mykiss

Document Type : Research Paper

Authors

1 Department of Aquaculture, Bab.C., Islamic Azad University, Babol, Iran

2 Department of Veterinary, Bab.C., Islamic Azad University, Babol, Iran

3 Fisheries Department, La.C., Islamic Azad University, Lahijan, Iran

4 Caspian Sea Ecology Research Institute, Fisheries Science Research Institute, Agricultural Research, Education and Extension Organization, Sari, Iran

10.22124/cjes.2025.8884

Abstract

Aeromonas hydrophila is one of the most significant and prevalent bacteria in aquaculture, particularly in fish farming. In this study, the effects of some killing methods of A. hydrophila on liver enzymes, biochemical parameters, and gene expression in rainbow trout, Oncorhynchus mykiss were evaluated. Four groups of 20 fish, each with an average weight of 5 g, with three replicates, were exposed to live A. hydrophila and heat, formalin, and UV-killed bacteria via intraperitoneal injection. The results showed that levels of liver enzymes AST and ALT did not differ significantly among the treatments (p > 0.05). Blood biochemical analysis revealed a significant increase in total protein levels in the treatment groups compared to the control (p < 0.05), while no significant differences were observed in albumin levels (p > 0.05). The expression of immune-related genes (TNF-α and IL-6) varied significantly among treatments, with the formalin treatment showing the highest expression levels (p < 0.05), and the control group showing. These findings suggest that inactivation of A. hydrophila with formalin is more effective in enhancing the immune response of rainbow trout compared to heat or UV inactivation methods.

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