Microflora associated with healthy and diseased turbot (Scophthalmus maximus) from three farms in northwest Spain

Abstract

A comparative analysis of the microbiological quality of three turbot (Scophthalnus maximus) farms (A, B, and C) located in Galicia (northwest Spain) is given. The microbial load and types of bacteria in the internal organs (liver and kidney) of apparently healthy fish was monitored over a year, and all the disease problems occurring during this survey were analyzed. The percentage of healthy turbot in which positive bacterial growth was obtained was relatively high in the three ongrowing facilities. Farm A exhibited the poorest conditions of fish health with an average of 42% fish infected, while farm B showed the best microbiological quality with 27% of turbot harbouring bacteria in the internal organs. In all three farms, a wide range of bacteria was found in healthy turbot with Vibrio (V. splendidus-V pelagius, Vfisheri-V harveyi and Vibrio spp.) and Pseudomonas spp. being the predominant groups comprising at least 80% of the total bacterial isolates in each farm. The highest number of pathological problems (22) with the most diverse bacterial flora occurred in farm A. Vibrio spp. and Pseudomonas spp. were the most prevalent bacteria recovered from diseased turbot. Haemorrhages in palate and jaws, tail and fins, and ulcerative lesions were the most frequent external clinical signs of diseased fish recorded in the three farms. However, it was not possible to associate a particular bacterial species with a specific pathology. Routine use in farm A of oxolinic acid and nitrofurantoin may have led to the development in the Vibrio strains of resistances to both chemotherapeutants (up to 25%).

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“…According Toranzo et al (1993) (Nishizawa et al, 2006) that was confirmed by recent survey of VHS in Turkey (Işıdan and Bolat, 2011). High level of diseased fish in BST stock could be related to combination of permanently acting stress environmental factors conjugated with different types of pollution, including chemical and organic agents; with permanent destruction of nursery, stock feeding and spawning grounds through different anthropogenic activities on the shelf and deep water environment; and thereafter permanent stress reducing its immune defense system and contamination by various pathogens (both bacterial or virus origin).…”

Bacterial Community Associated with Fish and Water from Congonhas River, Sertaneja, Paraná, Brazil

“…From these groups, Micrococcus and Lactobacillus were not detected in the water, of which, however, Flavobacterium strains were also isolated. The presence of these bacteria both in the aquatic environment and in the internal fish organs have been often observed (Sugita et al, 1985;Sakata, 1989;Toranzo et al, 1985Toranzo et al, , 1993Cahill, 1990). Aeromonas was the most abundant group in the fish, while, in global terms, the Gram-negative aerobic bacteria (specially Flavobacterium and Acinetobacter) were predominant in the water of the Congonhas River.…”

Antigenic characterization of Enterococcus strains pathogenic for turbot and their relationship with other Gram-positive bacteria

“…In Spain, the isolation of such bacteria from dying, farmed turbot Scophthalmus maximus was very uncommon until 1992 (Toranzo et al 1990(Toranzo et al , 1993a(Toranzo et al , 1994a; however, this situation now appears to be changing.…”