Ulcerative skin and fin lesions in reared turbot, Scophthalmus maximus (L.)

Abstract

Abslracl. In this report, the authors describe the evolution of an ulcerative disease that occurred during July and August 1986 in cultured juvenile turbot, Scophthalmus maximus (L.), in northwestern Spain. The daily tish mortality ranged from less than 1 to 7-5%, and the total ot cumulative losses were 23-2%. The start of the epizootic was closely associated with a sudden increase of water temperature to values higher than 20X. Peaks of mortality were observed during the development ol the disease. Affected turbot showed erratic swimming, respiratory distress and inappetcncc. The lesions began as white discoloured foci on the skin, operculum, and base of dorsal and caudal tins which could suffer a total destruction of the intcrradial membrane. In an advanced stage of this condition, the epithelial surface of the centre of the lesions sloughed off and shallow and hacmorrhagic ulcers were produced. Three distinct areas were observed in the ulcerative lesions with a clear predominance of different microorganisms: (1) a peripheric pale zone invaded by a ciliate protozoan resembling Cryptocaryon spp.; (2) an intermediate greyish-dark area containing large numbers of fastidious myxobaeteria which failed to grow in culture media; and (3) a central haemorrhagic zone where we have isolated two halophilic. urease positive Vibrio strains {closely related to V. carcharlae). No microbial involvement was detected in the internal organs of affected fish. The virulence assays conducted with the Vibrio strains failed to reproduce the signs of the disease, cither by intraperitoneal inoculation or by water challenge after skin abrasion. The use of alternate baths of formalin/malachite green and nitrofurazone resulted in an effective therapy to control the mortalities.

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“…WG and SGR of fish increased with increasing dietary protein level from CP30 up to CP50 and then stable from CP50 up toCP60 diet. Similar trends have been demonstrated for other flat fish species (Caceres-Martinez et al 1984;Devesa et al 1994;Kim et al 2002;Lee et al 2003;Imsland et al 2016). These unchanged growth performances of fish fed diets containing protein levels above the optimum probably due to decreasing available energy for growth and inadequate nonprotein energy necessary to de-aminate and excretion of the excess amino acids absorbed (Jauncey 1982;Vergara et al 1996;Kim et al 2002).…”

Experimentally induced marine flexibacteriosis in Atlantic salmon smolts Salmo salar. I. Pathogenicity

“…Tenacibaculum maritimum is the causative agent of marine flexibacteriosis in a number of cultured fish species worldwide (Wakabayashi et al 1986, Devesa et al 1989, Bernardet et al 1990, Chen et al 1995, Kusuda & Kawai 1998, Ostland et al 1999. In Tasmania, Australia, the disease has affected Atlantic salmon Salmo salar, rainbow trout Oncorhynchus mykiss, greenback flounder Rhombosolea tapirina and striped trumpeter Latris lineata (Handlinger et al 1997).…”

Epizootic study in a turbot farm: bacteriology, virology, parasitology and histology

“…Until now, these species of Vibrio were isolated in Galicia mainly from complex pathological syndromes where a variety of different microorganisms (myxobacteria, parasites, viruses) or tumoral processes (Devesa et al, 1989, Lamas et al, 1990 were involved in the disease. We have not detected the halophilic pathogenic vibrios V. ordallii and V. salmonicida in our area.…”

“…Myxobacteria, pseudomonads and Gram-positive cocci have been sporadically found in gills, skin lesions and internal organs of turbot, but always in mixed infections with Vibrio species or parasites (Devesa et al, 1989). also reported the presence in Galicia of Aeromonas salmonicida and Renibacterium salmoninarum isolated from salmon and trout reared in sea water; these have not been detected in turbot.…”

“…Matthews and Matthews (1980) reported the microsporidian Tetramicra brevifilum which produced small xenomas that gave rise to large cystic formations in skeletal muscles of turbot along British coasts. Devesa et al (1989) described the presence of the ciliate Cryptocaryon sp. associated with ulcers and tin lesions in cultured turbot from Galicia.…”