Photo: Skretting

Skretting Unveils Two Decades of Innovation in RAS Feed for Optimal Water Quality and Fish Health

NORWAY
Monday, June 16, 2025, 00:10 (GMT + 9)

The aquaculture leader highlights its patented fecal binding solutions and dedicated research, crucial for the success of recirculating aquaculture systems, as shared by veteran expert Steven Backman.

Maintaining pristine water quality is paramount for the success of Recirculating Aquaculture Systems (RAS), and at the heart of this challenge lies the effectiveness of feed in creating stable fecal matter. Skretting, a global leader in aquaculture feed, has been at the forefront of addressing this critical factor through decades of dedicated research and development.

"Over the last 25 years, Skretting Aquaculture Innovation (AI) has been patenting, working on and continuously developing our revolutionary faecal binding solution," explains Ingunn Stubhaug, Senior Researcher at Skretting Aquaculture Innovation. Stubhaug notes that the company has employed both established and new methods to evaluate binder efficacy, also considering different life stages for optimal fecal binding and superior growth.

Skretting North America was a pioneer in 2011, offering customers a salmon feed for full grow-out in RAS that incorporated this patented fecal binding solution. Steven Backman, a retired Skretting veterinarian, widely recognized as the 'grandfather of fish health veterinary medicine in Atlantic Canada,' witnessed this pivotal development. Backman recently shared insights into the profound importance of clean water for fish in RAS systems, how Skretting's feed has contributed to this, and observations from his extensive career.

"Skretting has always recognized the relationship between good water quality, animal welfare, and good growth efficiency. This is even more apparent with RAS-based farming methods," states Backman.

The Veterinarian's Perspective: Why Water is Life

With 36 years of experience at Skretting, Backman emphasizes that water is the fundamental life support medium for fish, providing oxygen, removing carbon dioxide, and flushing metabolic waste products like ammonia. He consistently heard from farmers that the system's capacity to support fish health and well-being is strongly influenced by the waste load, with a key factor being digestion by-products.

"Soft faeces, which disperse quickly, pass through mechanical filters, increase particle load, which end up in the bio-filter increasing its workload and limit capacity," Backman explains. These particles also diminish the efficiency of UV treatment systems, ultimately leading to less efficient production. He highlights a crucial breakthrough in RAS diets: the ability to make feces more stable and resistant to dispersal. This stability ensures feces remain intact longer, facilitating their removal by mechanical filters before overwhelming the bio-filter or impeding UV systems. Lower organic loads in the water reduce opportunities for bacterial growth, leading to a decreased risk of gill diseases, lower metabolic demands on the fish, better growth efficiency, improved welfare, and reduced operational costs.

Beyond the Fish: Benefits for Systems and Farmers

Backman notes that Skretting North America's customers were among the first to utilize RAS feeds for grow-out in 2011, and later, RCX feeds in 2017 with Optiline RCX Organic for Superior Fresh. He describes the satisfaction of providing products that enhance profitability and ease the workload for farmers in what he calls an "underappreciated profession."

RAS, he explains, is more than just a land-based facility; it's a "symbiotic relationship between the fish being raised and the biologic ecosystem purifying their environment," supported by sophisticated engineering systems. Feed quality impacts all three components. In traditional systems, feed focused primarily on fish requirements, but in RAS, fecal particles can burden bio-filters, increasing oxygen demand, encouraging off-flavor compounds, and raising energy use. By ensuring highly digestible feeds and binding feces with specialized techniques, Skretting supports optimal growth and lower feed conversion ratios. This also translates to lower energy consumption, reduced oxygen demand, and less heat loss through CO2 stripping for the entire system.

Continuous Innovation and a Memorable Success

Skretting continues to lead advancements in RAS feeds through ongoing research at purpose-built RAS research farms in Lerang, Norway, and Pargua, Chile. These facilities allow for the assessment of novel ingredients under real-world conditions to determine their effects on both the fish and the RAS system.

Backman's career includes a particularly memorable interaction in 2018 with Dr. Steve Summerfelt, a pioneering RAS systems engineer and his mentor since 2004. After developing new RAS systems for a full-scale salmon farm and aquaponics system at Superior Fresh, Dr. Summerfelt contacted Backman about Skretting's new RCX concept. Backman recalls being both excited and "a little nervous" as Summerfelt was a leading researcher in these systems. "For us at Skretting, failure was not an option," Backman states. He was delighted to hear Summerfelt's positive feedback: the feed was "amazing," the fish thrived, and water quality remained "perfect," validating years of hard work. As RAS systems evolve, so too must feed design, a principle Skretting continues to uphold.

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