of bacterial infections (specifi c pathogens or unspecifi c opportunistic
bacteria) and of the host-bacteria interactions.
Tailored solutions should be developed for each case. In this sense,
matured water, green water, biofi lters or immunostimulants are more
unspecifi c (general) tools, than prebiotics, probiotics or symbiotics. All
of them are directed to prevent or to enhance particular bacterial groups
and would be suitable when larval mortality is attributed to opportunistic
bacteria. The interference with quorum sensing would be applied to
prevent specifi cally bacterial infections due to pathogens which use
quorum sensing regulated virulence expression. The use of bacteriophages,
highly specifi c, would be a strategy to be used only when the aetiology of
infections has been proved to correspond to a specifi c pathogen.
How the host reacts to the presence of a particular microbiota should
be a subject of further research. Long-term effects also need to be studied.
The development of new molecular tools will certainly improve our
knowledge on microbial ecology and host-microbe interactions, and on
the underlying in vivo mechanisms of action of the different strategies
available but not suffi ciently understood in many cases.
Acylated homoserine lactones
Colony forming units
Denaturing gradient gel electrophoresis
Expressed sequenced tags
Fluorescence in situ hybridization
National centre for biotechnology information
Polymerase chain reaction
Recirculating aquaculture systems
Abelli, L., Randelli, E., Carnevali, O. and Picchietti, S. (2009). Stimulation of gut immune
system by early administration of probiotic strains in Dicentrarchus labraz and Sparus
aurata . Trends Comp. Endocrinol. Neurobiol. 1163: 340-342.
Amann, R.I., Binder, B.J., Olson, R.J., Chisholm, S.W., Deveroux, R. and Stahl, D.A. (1990).
Combination of 16s rRNA-targeted oligonucleotide probes with fl ow cytometry for
analyzing mixed microbial populations. Appl. Environ. Microbiol. 56: 1919-1925.
Andrews, J.H. and Harris, R.F. (1986). r- and K-selection in microbial ecology. Adv. Microb.
Ecol. 9: 99-147.
Arcand, S.L., Mes-Masson, A.M., Provencher, D., Hudson, T.J. and Tonin, P.N. (2004). Gene
expression microarray analysis and genome databases facilitate the characterization of a
chromosome 22 derived homogeneously staining region. Mol. Cardinog. 41: 17-38.