Morphological and Hematological Symptoms of Aeromonas Hydrophila Infections in Pelteobagrus Fulvidraco

Abstract

1. Abstract Aeromonas hydrophila is a gram-negative conditional pathogen of the genus Aeromonas in the family Vibrionaceae that generates exotoxins and other virulence factors that can cause pathological alterations in the tissues and organs of numerous aquatic animals. A. hydrophila infection can cause large-scale illness in Pelteoba-grus fulvidraco aquaculture, which can cause fish mortality and financial losses for the aquaculture sector. In this study, different concentrations of A. hydrophila (9.00×10 2 , 9.00×10 5 , and 9.00×10 8 CFU/mL) were used to infect healthy P. fulvidraco at room temperature, and the pathological changes and blood cell concentrations of the diseased fish were investigated using morphologi - cal observation and blood cell count. The findings revealed that A. hydrophila infection caused lesions in the gills, kidney, liver, and stomach of P. fulvidraco , manifesting as hemorrhage, ascites, and septicemia. As the concentration of A. hydrophila infection increased, the tissue damage of P. fulvidraco became more serious and the hemocyte concentration tended to decrease. However, there was a recovery in the decrease of hemocyte concentration at a lower bacterial infection concentration (9.00×10 2 CFU/mL). The results of this study demonstrated that P. fulvidus hemocyte concentrations were resistant to low concentrations of A. hydrophila (9.00×102 CFU/mL), and the morphological and blood cell concentration changes can provide a scientific basis for determining and identifying A. hydrophila infection in aquaculture production.