Effectiveness of Probiotic Phaeobacter Bacteria Grown in Biofilters Against Vibrio anguillarum Infections in the Rearing of Turbot (Psetta maxima) Larvae

Abstract

The rearing environment of first-feeding turbot larvae, usually with high larvae densities and organic matter concentrations, may promote the growth of opportunistic pathogenic Vibrionaceae bacteria, compromising the survival of the larvae. The aim of this study was to assess the effectiveness of the biofilm-forming probiotic Phaeobacter 27-4 strain grown on a ceramic biofilter (probiofilter) in preventing Vibrio anguillarum infections in turbot larvae. In seawater with added microalgae and maintained under turbot larvae rearing conditions, the probiofilter reduced the total Vibrionaceae count and the concentration of V. anguillarum, which was undetectable after 144 h by real-time PCR. The probiofilter also improved the survival of larvae challenged with V. anguillarum, showing an accumulated mortality similar to that of uninfected larvae (35-40 %) and significantly (p < 0.05) lower than that of infected larvae with no probiofilter (76 %) due to a decrease in the pathogen concentration and in total Vibrionaceae. Furthermore, the probiofilter improved seawater quality by decreasing turbidity. Phaeobacter 27-4 released from the probiofilters was able to survive in the seawater for at least 11 days. The bacterial diversity in the larvae, analysed by denaturing gradient gel electrophoresis, was low, as in the live prey (rotifers), and remained unchanged in the presence of V. anguillarum or the probiofilter; however, the probiofilter reduced the bacterial carrying capacity of the seawater in the tanks. Phaeobacter-grown biofilters can constantly inoculate probiotics into rearing tanks and are therefore potentially useful for bacterial control in both open and recirculating industrial units.

Phaeobacter inhibens as probiotic bacteria in non-axenic Artemia and algae cultures

“…To circumvent the need for prophylactic use of antibiotics in aquaculture, the application of probiotics seems to hold great potential and previous studies have demonstrated a clear probiotic effect of the Roseobacter clade bacterium Phaeobacter inhibens in axenic model systems (D'Alvise et al, 2012(D'Alvise et al, , 2013Grotkjaer et al, 2016;Prol-García and Pintado, 2013). Our results demonstrate that moving P. inhibens from an axenic model system to a defined non-axenic, and ultimately to a completely non-axenic, live feed model system, does not interfere with the establishment of the potential probiont, nor with its antagonistic effects on the fish pathogenic bacterium Vibrio anguillarum.…”

Evaluation ofLactobacillus plantarumas a water additive on host associated microflora, growth, feed efficiency and immune response of giant freshwater prawn,Macrobrachium rosenbergii(de Man, 1879)

“…Probiotics play an important role in welfare of host by maintaining a healthier balance of intestinal microflora which not only provides a defensive barrier against colonization of harmful bacteria but also stimulates host immune system (Gomez & Balcazar ; Cain & Swan ; Gaggia, Mattarelli & Biavati ). Probiotics when used as water additive may act like a biological control agent and manipulate the microbial population of the environment by reducing or eliminating pathogenic micro‐organisms which is often realized as increase in animal survival (Luis‐Villasenor, Macias‐Rodriguez, Gomez‐Gil, Ascencio‐Valle & Campa‐Cordova ; de Souza, Suita, Leite, Romano, Wasielesky & Ballester ; Prol‐Garcia & Pintado ; Silva, Soares, Calazans, Vogeley, do Valle, Soares & Peixoto ; Zokaeifar et al . ).…”

Toxicity of Bioactive and Probiotic Marine Bacteria and Their Secondary Metabolites in Artemia sp. and Caenorhabditis elegans as Eukaryotic Model Organisms

“…Pseudoalteromonas, Roseobacter, and Vibrionaceae bacteria have been suggested as probiotics in aquaculture (7)(8)(9). However, our results suggest that several Pseudoalteromonas and Vibrionaceae strains may not be suitable, since they can be toxic to Artemia sp.…”

“…These species predominantly belonged to the Actinobacteria class, the Pseudoalteromonas genus, Roseobacter clade, and the Photobacteriaceae and Vibrionaceae families (3,5,6). Due to their antagonistic activity, live cultures of bacteria from Pseudoalteromonas, Phaeobacter, Ruegeria, and Vibrio genera are not only of interest as sources of novel pharmaceuticals but also as probiotics in fish and shellfish aquaculture systems (7)(8)(9).…”