Location: Aquatic Animal Health Research
Title: Toward understanding factors associated with outbreaks of motile aeromonas septicemia in channel catfish (ictalurus punctatus)Author
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Submitted to: Aquaculture America Conference
Publication Type: Abstract Only Publication Acceptance Date: 12/8/2022 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Motile Aeromonas septicemia (MAS), caused by virulent Aeromonas hydrophila (vAh), has severely impacted catfish farming in the southeastern United States since 2009. Conditions that trigger the onset of MAS outbreaks remain largely unknown. In this study, the effects of nutrients and select microbes in water on proliferation of vAh and severity of MAS in channel catfish were assessed. Results of the study demonstrated that both nutrient rich tryptic soy broth powder (TSBp, the microbiological growth medium) and the commercial fish feed supported vigorous growth of vAh in water. Challenge of fish in the vAh-propagated water at 24 h post inoculation (hpi) resulted in approximately 96% and 73% mortality, respectively. Co-inoculation of vAh with a vAh-antagonistic Pseudomonas mosselii or a non-antagonistic Aeromonas veronii in water had no significant effects on vAh growth and infection; nevertheless, P. mosselii protected fish against vAh infection (with approximately 79% of relative percentage of survival) when fish were briefly pre-immersed in P. mosselii-propagated water prior to challenge. Culture of vAh in situ described in this study was shown to be a useful method for mimicking vAh growth dynamics in response to nutrients and probiotics in relatively natural environment. Findings of this study would help understand the mechanism of MAS outbreaks and facilitate research on control and prevention of MAS. |
