Alternative methods of disease prevention and treatment in aquaculture

Background. In recent years, the use of antibiotics in aquaculture has raised increasing concern due to the development of microorganism resistance to antibacterial drugs and the negative impact on the ecosystem. Therefore, search for alternative methods for treating and preventing fish diseases has become an urgent task. Promising alternatives for the prevention and treatment of aquaculture species include the use of probiotics, prebiotics, synbiotics, postbiotics, phytobiotics, bacteriophages, and quorum sensing (QS) inhibition mechanisms. The state of the microflora of aquatic organisms is crucial for enhancing the organism’s resistance to infectious diseases. Thus, using agents that can positively influence the microbiota, exert antimicrobial effects, and modulate the immune system is essential for the effective development of the aquaculture industry. This article discusses some of the main fish diseases, the likelihood of which increases with the intensification of aquaculture. Bacteria of the genus Aeromonas are often the cause of diseases and financial losses in the industry. The work provides an overview of alternative methods for preventing and treating fish diseases that can reduce the use of antibacterial drugs, including the application of vaccines, probiotics, prebiotics, and bacteriocins.

Purpose. To investigate alternative methods of treatment and prevention of fish diseases.

Materials and methods. In the study, a method of collecting, analyzing, and systematizing of published scientific sources was used. The collection of literary information was carried out using reference databases such as Science Direct, Research Gate, Google Scholar, National Library of Medicine, Wiley Online Library, and others. To search for suitable scientific publications, keywords such as «aquaculture», «diseases», «bacterial fish diseases», «probiotics», «prebiotics», «synbiotics», «bacteriocins», «phytobiotics», and «quorum sensing» were used individually or in various combinations. The search period was limited to scientific works published between 2014 and 2024.

Results. As alternative methods, vaccination, quorum sensing inhibition, bacteriophages, as well as probiotics, prebiotics, phytobiotics, and others can be used. The state of the fish microbiome has an important impact on the likelihood of developing of infectious processes. For example, it has been reported that fish with a healthy microbiome more effectively controlled and suppressed the colonization and dissemination of bacteria of the genus Aeromonas than fish with a disrupted microbiota. Currently, probiotic microorganisms are most commonly used as agents that can influence the microflora and correct the microbial balance [36]. Probiotics are most commonly represented with bacteria, including species from cultures Bacillus sp., Lactococcus sp., Micrococcus sp., Carnobacterium sp., Enterococcus sp., Lactobacillus sp., Streptococcus and Weissella sp. Some strains of yeast and algae may be used too. Probiotics are most commonly represented with a group of lactic acid bacteria, as among all microorganisms with registered probiotic properties, they are considered to have a higher safety profile. They can produce antimicrobial substances and positively influence the immune system of the macroorganism. Probiotics used in aquaculture must undergo a special assessment to determine their potential for application, taking into account the specifics of the industry. The main spectrum of action of probiotic microorganisms in the intestines of aquatic organisms lies in their anti-adhesive effect against pathogenic strains, the production of antimicrobial substances (including bacteriocins and defensins), competition with pathogenic flora, enhancement of the host’s resistance properties, alteration of the intestinal pH level, and activation of the immune system.

Conclusion. Thus, despite the intensification of aquaculture and the increased likelihood of infectious diseases in aquaculture species, the worsening issue of antibiotic resistance and the irrational use of antibacterial drugs necessitate the development and implementation of alternative methods for controlling fish diseases.