Saprolegnosis: dissemination in aquaculture and control methods

Saprolegnia spp, the causative agent of which is aquatic mold fungi, affects fish and spawn during factory hatchery and is one of the problems when growing avaculture in industrial conditions. The review describes control methods of Saprolegnia spp. Traditional methods of saprolegnia control are chemical compounds such as malachite green, purple "K" and formalin, which have carcinogenic and mutagenic effects. Safer but somewhat outdated methods are the treatment of spawn with incubation of boric acid and hydrogen peroxide, as well as water ozonization. Alternatives to these methods of control may be natural biologically active substances: thyroxine and cortisol, bark extract Drimys winteri, chitosan. Besides, various isolates of microorganisms are used as biological methods of saprolegnosis control in aquaculture, namely: bacteria of the genus Pseudomonas, Aeromonas, Bacillus subtilis, Pantoea agglomerans. The use of marine algae containing sulfated polysaccharides, including fucoidan, to control saprolegnosis has been confirmed. Fucoidan has been shown to have wide biocidal activity, but its antimicrobial properties have not been studied. In this regard, the study of the influence of the structure of fucoidan on its antimicrobial properties is a promising trend in the search for new safe means of saprolegnosis control.