A number of studies have attempted to demonstrate the
antibacterial properties of skin mucus from different species of fish
such as turbot, Atlantic salmon, rainbow trout, gold fish, seabass,
seabream, flounder, barramundi, cichlid and yellowtail . However,
most have suffered from alack of definitive data concerning the
virulence of the organisms used for in vitro assessment of
antibacterial properties of skin mucus. Most of pathogens which
have been investigated are isolates of Aeromonas spp.,
Cytophaga/flexibacter-like bacteria, Vibrio spp., flavobacterium
sp., Pseudomonas sp., Yersinia spp. and PasteureUa sp. The data
show that there is a variation in the quality of the mucus from the
fish species investigated.
In general, the antibacterial activity of mucus, when tested in vitro,
was inversely related to the in vivo pathogenicity of the same
isolate of the pathogen. Growth inhibition of bacteria by fish
mucus emphasises two criteria for practical aquaculture, firstly,
emphasis should be on the maintenance of a good layer of external
mucus surfaces by careful management and good nutrition and
secondly, selection of fish species which inherently possess strong
inhibitory activities against pathogens in their mucus may be a
useful strategy.
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