Pathogens in aquaculture Ubiquitous antimicrobial activity of a new feed additive against several pathogens in aquaculture farming systems
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by Maxime Hugonin and StĂŠphane Frouel, MiXscience, France
s a potential protein source of tomorrow, for a population always growing, the aquaculture industry is facing several challenges. To reach the demand, the yield production must be maximised. In this way, farmers always increase their stocking densities, going from intensive culture to super-intensive ones, leading to new pathogens appearances and propagations with a multiplication of disease outbreaks. The first people impacted by these issues are the farmers. This pathogenic pressure significantly impacts the economics of farming. The main solution to this issue remains the use of antibiotics, thanks to their easy use in curative treatment and their visible and rapid effects. Unfortunately, the use and abuse of chemicals raises public health concerns, because of antibiotic
resistance, and adverse effects on the environment. Then, this remedy participates to the bad image associated to aquaculture production and produces shifts in the public opinion. Active researches are ongoing in their hard work to explore alternatives. This article reports on the use of a natural phytogenic, based on specifically selected plant extracts, to control a broad spectrum of pathogens in aquaculture systems. The story of the product started from a laboratory, associated with RID trials, and ended in-field at larger and commercial scale. Thus, the antimicrobial effects of this phytogenic have been investigated both in vitro and in vivo, which provides a robust and pragmatic feedback on its benefits.
Mechanisms of actionÂ
The large spectrum of the antimicrobial activity of this feed additive is based on particular mechanisms of action with common targets among pathogens: the proteins. The anti-
Figure 1: (Below) Nature of potential ways of penetration of SOCs into cell Figure 2: (Top right) Denaturation of microbial proteins by fixation of SOCs on disulfide bridges Figure 3: (Bottom right) Functional metabolic alterations by SOCs contained in the phytogenic
22 | January 2019 - International Aquafeed