Chileans discover powerful alternative against pathogens in salmon farming

A recent study opens new perspectives for the development of sustainable solutions in salmon farming, by demonstrating that nettle extract (Urtica magellanica), a species native to Chile, has relevant antibacterial and biostimulant properties against fish pathogens.

The research, carried out by scientists from the University of Concepción and the University of the Americas, evaluated the methanolic extract of leaves of the nettle, identifying a high concentration of phenolic compounds, with a content of 633,394 mg/eq of gallic acid per 100 grams.

Among the compounds detected in the extract, phenolic acids such as gallic, chlorogenic, ferulic, and synaptic stand out, in addition to flavonoids such as quercetin, rutin, kaempferol, and isorhamnetin.

Antimicrobial and biostimulant 

In the in vitro experiment conducted by the experts, an effective antibacterial activity was determined, as the extract showed inhibitory effects on important bacterial pathogens in aquaculture.

“The antibacterial effect on Aeromonas salmonicida and Flavobacterium psychrophilum showed a minimum inhibitory concentration (MIC) of ≤3.0 mg/mL. In contrast, Vibrio anguillarum showed an MIC ≤0.75 mg/mL,” the authors explained.

The study also addressed the effect of the extract on the CHSE-214 salmonid cell line. The results showed a dose-dependent response, providing key information for its potential application.

Additionally, at low concentrations, between 0.012 and 0.023 mg/mL, the extract reduced cell viability by 50%, suggesting possible cytotoxic effects within certain ranges. However, at a concentration higher than 0.375 mg/mL, a significant increase in cell viability was observed, reaching 182%.

This dual effect suggests that, under controlled conditions, the extract could not only act as an antimicrobial agent, but also as a biostimulant capable of promoting the cellular response, depending on the dose used.

Although the in vitro (laboratory) results are promising, the researchers caution that these effects still need to be validated under in vivo conditions (in the animal).

“Consequently, considering the demonstrated effect of the extract and its possible interactions in complex systems, in vivo validation is required to consider it a sustainable strategy against aquatic pathogens,” the experts concluded.

Read the abstract of the study titled “Antibacterial and biostimulatory activity of urtica magellanica extract on fish pathogenic bacteria and CHSE-214 salmonid cell line”, here.