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This work describes the first isolation of Streptococcus iniae in red porgy, Pagrus pagrus (L.), and the first European isolation of this pathogen in gilthead seabream, Sparus aurata (L.). In both farmed fish species, infection resulted in lethargy, anorexia, abnormal swimming, exophthalmia and sudden death, with mortality rates of over 25% in red porgy and 10% in gilthead seabream. Beta-haemolytic Gram-positive cocci, catalase negative and oxidase negative, were isolated in pure culture from internal organs. Conventional and rapid identification systems, and 16S rRNA gene partial sequencing were used to identify the causative agent of the natural disease. LD50 trials were carried out to show the virulence of this isolated strain in these species, with values of 1.7 × 104 CFU per fish in red porgy and 1.32 × 105 CFU per fish in gilthead seabream. The most prominent lesions were meningoencephalitis and multifocal infiltration of macrophage cells in the kidney and spleen. [ABSTRACT FROM AUTHOR]

The establishment and partial characterization of a continuous cell line from the dorsal fin of red sea bream, Pagrus major, are described. The cell line, designated RSBF-2, has been subcultured for more than 100 passages since its initiation in November 2000. It was optimally maintained at 28 °C in Leibovitz L-15 medium with 10% foetal bovine serum. Propagation of RSBF-2 cells was serum dependent and exhibited low plating efficiency (<1.7%). Aside from long-term cryopreservation, the cells could also be kept at 4 °C for 72 days. The distribution of the chromosome number was 38–98 with a mode of 48. The RSBF-2 cell line was susceptible to red sea bream iridovirus but only produced a few rounded and refractory cells. Virus-inoculated RSBF-2 cells were then subcultured to generate a persistently infected cell line. RSBF-2 was also very sensitive to the extracellular products of Photobacterium damselae ssp. piscicida and produced significant fluorescent signals after transfection with pEGFP-C3. Analysis of mitochondrial cytochrome b gene sequences revealed 99% identity between the cell line and Pagrus major. [ABSTRACT FROM AUTHOR]

Four bacterial isolates from farmed gilthead sea bream, Sparus aurata, included in a previous study as members of the Vibrionaceae and Pseudomonodaceae and the genus Micrococcus, have been evaluated for their adhesive ability to skin and intestinal mucus of farmed Senegalese sole, Solea senegalensis, and their antagonistic effect on Vibrio harveyi, a pathogen of sole. These isolates showed higher adhesion to sole mucus than the pathogenic strains of V. harveyi assayed. Only two of the isolates showed antagonistic activity to V. harveyi. Interactions of the four isolates with V. harveyi in respect of adhesion to skin and intestinal mucus under exclusion, competition and displacement conditions were studied. Three isolates were able to reduce the attachment to skin and intestinal sole mucus of a pathogenic strain of V. harveyi under displacement and exclusion conditions, but not under competition conditions. The in vivo probiotic potential of isolate Pdp11 was assessed by oral administration followed by challenge with the pathogenic V. harveyi strain Lg14/00. A group of 50 Senegalese sole received a commercial diet supplemented with 108 cfu g−1 of lyophilized Lg14/00 for 15 days. A second group of fish received a non-supplemented commercial diet. After challenge the mortality of the fish receiving the diet supplemented with the potential probiotic isolate was significantly lower than that in the fish receiving the non-supplemented commercial diet. This study has shown that the ability to interfere with attachment of pathogens, as well as the adhesion to host surfaces, are suitable criteria for selection of candidate probiotics for use in the culture of Senegalese sole. [ABSTRACT FROM AUTHOR]

In order to clarify the effectiveness of ultrasonication on vaccine delivery, juvenile sea bream, Pagrus major , were treated with eight different ultrasonic methods. A mixed vaccine against Vibrio alginolyticus and V. anguillarum was used to immunize the fish. The intensity and frequency of the ultrasound were 280 mW cm–2 and 35 kHz, respectively. The ultrasonic methods included continuous or pulsed ultrasound for 3 min, and continuous or pulsed ultrasound for 3 min before and/or after immersion for 3 min. Of all the eight ultrasonic methods tested, `pulsed ultrasound followed by immersion' and `immersion, pulsed ultrasound, and followed by immersion again' provided the best protection, which were comparable with protection of fish immunized by intraperitoneal injection. Moreover, the convenience of applying these two ultrasonic methods for immunization was comparable with the immersion method and was much better than intraperitoneal injection. If 2 × 108 CFU mL–1 of this mixed vaccine was used for vaccination repeatedly five times by ultrasonic methods, it could still produce good protection for the immunized sea bream. Therefore, the ultrasonic method is an effective and practical approach for fish vaccination on a large scale. [ABSTRACT FROM AUTHOR]

Investigates the fecundity in vitro of Anoplodiscus cirrusspiralis (Monogenea) and examines at approximately weekly intervals, its spatial distribution, growth, longevity and mortality on a single juvenile snapper (Pagrus auratus) kept in an aquarium for ten months. Background on literature regarding the intensity of infection by monogenea on snapper; Mode by which estimates of longevity were determined.

Focuses on the use of needle biopsy technique for non-lethal sampling of liver tissue in snapper, Pagrus auratus. Effect of the biopsy technique on the health of the animal; Technological aspect of the biopsy needle; Importance of the technique for diagnostic procedure of hepatic disorder.

The monogenean Anoplodiscus cirrusspiralis infects the fins and nares of snapper. Pagrusauratus(Bloch & Schneider). The epidermis beneath the haptor in both inicrohabitats is eroded and the parasite attaches to the basement membrane by an adhesive secretion. Captive snapper suffered tin damage through high levels of infection by this parasite. Laboratory experiments showed A. cirrusspiralis to be adversely affected by reduced salinity and killed within 1 h by diluted sea water of <5% salinity. [ABSTRACT FROM AUTHOR]