The research focuses on Yersinia ruckeri, a major bacterial pathogen in rainbow trout.
Photo: Adobe Stock
A new Italian-Canadian research study offers promising evidence for a plant-based alternative to antibiotic use in rainbow trout aquaculture.
The study, undertaken by Italian feed manufacturer Vetagro in collaboration with Canadian contract aquaculture research organisation Onda, showed that microencapsulated phytogenic feed additives can significantly reduce mortality caused by Yersinia ruckeri, a major bacterial pathogen in rainbow trout farming.
Yersinia ruckeri poses a key challenge for rainbow trout farmers, causing high mortality rates and reduced growth performance, with effective treatment made even more complex due to the likelihood of chronic infections and asymptomatic carriers, Onda said, announcing the outcome of the research study via a press release.
The study, which was undertaken in order to validate Vetagro's proprietary formulation, found that two of Vetagro’s microencapsulated phytogenic feed prototypes reduced mortality by 26.3% and 29.3%, respectively, in infected juvenile rainbow trout, compared to a control group. The test feeds also maintained high levels of palatability, suggesting the feed is suitable for commercial application.
“Vetagro was founded by a group of professors from the University with the strategic mission to transform scientific innovation into market-ready solutions. Here we are now in 2025 putting science and experience in microincapsulation at the service of the aquaculture sector,” said Ester Grilli, Vice President and Head of Marketing and Innovation at Vetagro.
“We’re proud to have partnered with Vetagro on this forward-thinking research,” added Myrna Gillis, CEO of Onda. “This work exemplifies how scientific collaboration drives innovation - translating cutting-edge research into practical solutions for aquaculture producers navigating growing sustainability and regulatory demands."
Onda said that the study marked "a significant milestone in the shift toward antibiotic alternatives in aquaculture", lending weight to the role of advanced feed additives in tackling disease and improving fish welfare, while at the same time supporting performance and palatability.
