| dc.description.abstract | Summary
Background: The global warming; the overfishing of the sexually mature adult fish
(the spawners) and the offspring; the environmental pollution and parasites have
significant impact on severe decline in the European eel (Anguilla anguilla) stock.
Objectives: For restocking purposes, several research projects about the elaboration
of captive breeding methods and hatchery technology of eel, have been initiated. The
detection of piscine pathogens and the development of effective therapeutic and
prevention strategies against their infections during the early life stages in fish (eggs,
larvae, fry, and smolts) under controlled conditions are essential for successful work.
Materials and Methods: The aim of the present study was to identify the patho gen(s), and to make proposal for the possible treatments against the infection of
the developing eel embryos, that produced by the controlled reproduction process
following hormone-induced sexual maturation of female European eel. The patho genic bacteria were isolated on different selective media. They were characterised by
morphological –, microscopic examinations and with some biochemical tests. Their
taxonomic status was verified by using the Biolog MicroStation ID system, and by
amplification and sequencing of the 16S rDNA genome region. Then their antimicro bial sensitivity was checked by Kirby-Bauer disc diffusion method using 10 various
antibiotics (ampicillin, chloramphenicol, cotrimoxazole, enrofloxacin, erythromycin,
florfenicol, furazolidone, gentamicin, oxytetracykline, polymyxin-B).
Results and Discussion: The phenotypic and genotypic microbiological assays
detected the presence of only one dominant species; that was the Vibrio cyclitroph icus, a member of Vibrio splendidus clade. The pathogenicity of these bacteria to
larvae of molluscs and shrimps has been already known. Their emergence in the
closed experimental system may be the result of the artificial sea water prepared
from contaminated sea salt. Based on the antibiogram of the isolated bacterium
strain the use of chloramphenicol and a consequent formalin treatment of the water
for general disinfection is suggested. | en_US |
