Antimicrobial activity in bacteria isolated from Senegalese sole, Solea senegalensis, fed with natural prey

Abstract

Intestinal bacteria in marine ¢sh may produce antimicrobial substances which inhibit pathogenic bacteria. The aim of this study was to determine the in£uence of a change of ¢sh diet on the antimicrobial activity of the culturable aerobic gut micro£ora of Senegalese sole, Solea senegalensis. Pre-adult 15month-old ¢sh previously fed on an arti¢cial diet, were fed polychaetes (Hediste diversicolor), which form part of the natural diet of Senegalese sole. Samples were taken 0, 3 and 6 weeks after start of the experiment from the stomach, small and large intestine of the ¢sh. The bacterial strains isolated from these samples were sub-cultured to pure cultures and stored at À 80 1C. Several biochemical tests were run to obtain some basic phenotypic characteristics of the isolated strains. Ampli¢cation and sequencing of 16S rDNA fragments were used to identify the majority of the bacterial strains isolated. The identi¢cation by use of this molecular approach gave results in agreement to the phenotypic characterization. Feeding with polychaetes signi¢cantly increased (Po0.05) the numbers of presumptive Vibrio isolates in the gut. The number of bacterial strains with antimicrobial activity, as determined by two in vitro approaches, was signi¢cantly (Po0.05) increased by feeding with polychaetes.

Microbial manipulations to improve fish health and production – A Mediterranean perspective

“…Positive effects of probiotic strains on sea bream larvae have also been reported by Makridis et al [83] and Avella et al [63]. Makridis et al [83] added six bacterial strains (Cytophaga spp., Roseobacter spp., Ruegeria spp., Paracoccus spp., Aeromonas spp. and Shewanella spp., isolated from well-performing live food cultures) to sea bream eggs.…”

Use of probiotic bacteria in the rearing of Senegalese sole (Solea senegalensis) larvae

“…The bacterial strains used in this study were isolated from the culturable heterotrophic gut microflora of Senegalese sole, S. senegalensis , juveniles fed natural prey (Makridis et al 2005a). Two of these bacterial strains were gram‐negative and oxidase‐positive, were identified using amplification and sequencing of rDNA fragments as Vibrio sp.…”

“…Three bacterial strains, which showed in vitro inhibition against two fish pathogens (Makridis, Martins, Tsalavouta, Catalao Dionisio, Kotoulas, Magoulas & Dinis 2005a), were used in this study in the rearing of Senegalese sole larvae and postlarvae. The aims of this study were to determine the effect of these candidate probiotic strains on: (i) survival of unfed sole yolk‐sac larvae ( in vivo test), (ii) survival of larvae and postlarvae in a feeding experiment, and (iii) the numbers of culturable bacteria present in the water and the fish gut.…”

Probiont niche specialization contributes to additive protection against Vibrio owensii in spiny lobster larvae

“…The gut microenvironment appears to be particularly competitive, where different Vibrio species inhabiting similar niches may produce distinctive bioactive compounds (Wietz et al, 2010) to enhance ecological success. This is supported by the isolation of many antagonistic and siderophore-producing vibrios from the gastrointestinal tracts of aquatic organisms (Makridis et al, 2005;Fjellheim et al, 2007;Sugita et al, 2012). It is well recognized that the establishment of probionts in the digestive tract is a possible means of controlling enteropathogen proliferation in invertebrates and fish (Sugita et al, 1998;Rengpipat et al, 2000;Balcázar and Rojas-Luna, 2007;Li et al, 2007;Avella et al, 2011;Boonthai et al, 2011).…”