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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Aquatic Animal Health Strategies

Location: Aquatic Animal Health Research

Title: Clinical, hematological and biochemical alterations in olive flounder, Paralichthys olivaceus following experimental infection by Vibrio scophthalmi

Authors
item Qiao, G. -
item Park, S.I. -
item Xu, Dehai

Submitted to: Canadian Journal of Fisheries and Aquatic Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 21, 2012
Publication Date: September 27, 2012
Repository URL: http://handle.nal.usda.gov/10113/56373
Citation: Qiao, G., Park, S., Xu, D. 2012. Clinical, hematological and biochemical alterations in olive flounder, Paralichthys olivaceus following experimental infection by Vibrio scophthalmi. Canadian Journal of Fisheries and Aquatic Sciences. 15(3):233-239.

Interpretive Summary: Hematological tests and analysis of serum constituents provide key values for monitoring fish health conditions as these approaches provide reliable information on metabolic disorders, deficiencies and health status before they become disease problems in cultivated fish. Regular monitoring of the hematological parameters of farmed fish can prevent losses due to fish diseases in aquaculture. Currently, there is not any information available on hematological changes of olive flounder following V. scophthalmi infection. In this study, hematological and biochemical alterations were determined for olive flounder infected by high virulent strain (HVS) and low virulent strain (LVS) of V. scophthalmi. The results demonstrated that the hematocrit value in infected fish declined from 23.4% at 0 h to 18.0% at 168 hours post infection. The total protein concentration in fish infected with the HVS was significantly higher than fish infected with LVS and non-infected control. Lysozyme activity was significantly different between infected and control fish. The HVS survived in serum and the cell number increased greatly, while cell number of LVS decreased. These changes in hematological characteristics in fish infected by V. scophthalmi can be used as an effective and sensitive index to monitor physiological and pathological conditions of fish. These results will be a benefit to fish health managers and producers for understanding pathogenic characteristics of the infected bacteria, preventing fish disease, and minimizing loss in aquaculture.

Technical Abstract: Hematological analysis can provide key values for monitoring fish health conditions. There is no information available on hematological changes of olive flounder following infection by Vibrio scophthalmi. In this study, hematological and biochemical alterations were determined for olive flounder infected by high virulent strain (HVS) and low virulent strain (LVS) of V. scophthalmi. Survival in serum, skin mucus and macrophages of olive flounder was also compared between HVS and LVS. The results demonstrated that the hematocrit value in infected fish declined from 23.4% at 0 h to 18.0% at 168 hours post infection. The total protein concentration in fish infected with the HVS was significantly higher than fish infected with LVS and non-infected control. Lysozyme activity was significantly different between infected and control fish. The HVS survived in serum and the cell number increased greatly, while cell number of LVS decreased. These changes in hematological characteristics in fish infected by V. scophthalmi can be used as an effective and sensitive index to monitor physiological and pathological conditions of fish. The survival and reproduction of V. scophthalmi in host serum, skin mucus and macrophages play a major role in systemic infection and can serve as a virulence indicator for different strains.

Last Modified: 7/24/2014