Response of Juvenile Danube Sturgeon (<em style="mso-bidi-font-style: normal;">Acipenser gueldenstaedtii) to <em style="mso-bidi-font-style: normal;">Aeromonas hydrophila: Histopathological and Hematological Findings

This study investigated the physiological and pathological responses of juvenile Danube sturgeon to Aeromonas hydrophila infection. Fish were intraperitoneally injected with ۰.۱ mL of A. hydrophila suspension (۱×۱۰⁸ CFU mL-۱). The experiment was conducted with three replicates per group (infected and control), each containing ۱۰ fish. Based on the challenge test results, mortality in the infected group began on day ۳ and continued progressively until day ۱۳. Additionally, swim bladder deflation, hyperemia, and hemorrhaging in the visceral organs were observed. Hematological analysis revealed that LYM, HGB, MCH, and MCHC values were significantly higher in the control group, whereas WBC and MCV levels were elevated in the infected group. Histopathological examination of liver tissues revealed prominent melanomacrophage centers and signs of necrosis. According to a semi-quantitative scoring model, regressive changes and inflammation were significantly higher in the infected group compared to the controls (P< ۰.۰۱). In conclusion, Aeromonas hydrophila demonstrates a highly pathogenic potential for juvenile Danube sturgeon, inducing rapid systemic deterioration and significant tissue damage. The findings confirm that this bacterium is capable of causing disease and lethal outcomes within a week, emphasizing the urgent need for preventive strategies in conservation and aquaculture management of this endangered species.

کلیدواژه ها:

Challenge test ، Fish ، Hematology ، histopathology ، Pathogen microorganism