Title : The presence of the bacterium vibrio harveyi in sea bass dicentrarchus labrax, In intensive fish farming In greece
Vibrio harveyi is an opportunistic pathogen bacterium, which affects Greek aquaculture in recent years, as it causes significant losses mainly in sea bass, Dicentrarchus labrax. The purpose of this study is to describe the cause, pathogenesis, clinical symptoms and preventive/therapeutic treatment of the infection from the specific bacterium in sea bass, in intensive farming conditions. Vibrio harveyi is a Gram (-), slightly curved, motile bacillus, belonging to the Vibrionaceae family and part of the normal intestinal microbiota of fish. Conditions of intense stress, changes in environmental parameters, presence of high parasite load in a fish population, can cause overgrowth of the bacterium and infect fish. Disease outbreaks are evident in farmed sea bass >10gr, mainly in summer/autumn, in water temperature >20°C. Affected fish show lethargy, anorexia, dark coloration, hemorrhages, erosions and ulcers on the skin, swelling of the abdominal cavity, exophthalmos, blindness and necrotic gills. Internally, there is splenomegaly, discoloration of the liver and catarrhal enteritis characterized by distention and hemorrhages of the intestinal wall with the presence of serous fluid in the lumen. Mortality depends on the coexistence of other pathogens, mainly endo- and ecto-parasites and/or other bacteria and can range from 5 to 30%. Diagnosis is based on the growth of Vibrio spp colonies on TCBS, Blood & Mueller Hinton agar and confirmation is based on molecular identification. Administration of immunostimulants, antibiotics after antibiogram and the implementation of fasting/change of food help to reduce mortality. Vaccine development is at an experimental stage and is a promising measure to prevent the disease.
What will audience learn from your presentation?
- This research will expand our knowledge of bacterial treatments in aquatic species, this knowledge is useful for teaching purposes also.
- This research can be extended in other diseases (microbial/fungal) in aquatic environment or in agriculture in general.