review of the literature relating to the antibacterial properties of piscine skin mucus

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.