- Feed One’s farm trials showed eels can grow successfully on a completely fishmeal-free diet.
- Field trials provided real-world evidence that fishmeal can be removed from eel feed.
- The breakthrough could help reduce aquaculture’s reliance on fishmeal amid cost and supply pressures.
Fishmeal has long been considered difficult to replace in eel feed. Beyond its nutritional value, high-quality fishmeal helps provide the kneadable texture required when feed is mixed with water.
Conventional eel feeds typically contain around 70% fishmeal, making the species one of the more challenging targets for fishmeal reduction efforts.
Eels’ dependence on fishmeal has been a pressure point for producers, especially as the industry faces rising fishmeal costs and supply uncertainty linked to fluctuating fish catches and unstable marine conditions, including those linked to El Niño.
Against this backdrop, Feed One developed Kamui ZERO, a feed that aims to reduce reliance on fishmeal.
The company has been working to reduce fishmeal in feed since 2016, when it developed a fish feed with 60% fishmeal. In 2023, it launched another product with 40% fishmeal content.
It is aiming to launch Kamui ZERO commercially this year, said the firm.
“We will contribute to sustainable eel farming by proposing a gradual reduction in fishmeal usage according to each farming environment, including the use of our already available low-fishmeal feed. We will continue to work with producers, conducting field tests to develop eel feed formulations that balance productivity and sustainability.”
Trials prove eels don’t need fishmeal
Working with eel farmers in Kyushu, the aquafeed producer conducted field trials comparing Kamui ZERO to its 60% fishmeal feed.
The experiment involved approximately 38,000 eels raised and monitored over two months.
Results showed that the fishmeal-free diet produced lower feed efficiency.
Nevertheless, the company reported that eels fed the fishmeal-free formulation were still able to feed actively and grow.
Growth rates in both treatment groups were approximately double their starting levels, providing evidence that eels can be reared successfully without fishmeal in the diet.
The trial demonstrated both the potential and the current limitations of fishmeal-free eel feed, said the firm.
It added that while further optimisation is required to improve feed conversion efficiency, the results suggest that complete removal of fishmeal is technically feasible.
The company noted that in a separate internal trial, eels fed 40% fishmeal feed achieved slightly lower feed efficiency than those receiving conventional feed.
However, the trial also demonstrated that the daily feeding rate of eels receiving the lower-fishmeal feed was equal to or greater than that of fish fed the traditional formulation.
The company believes these findings indicate that substantial reductions in fishmeal are possible while supporting growth and maintaining strong feed intake.
Moving forward, the company said it would continue working with eel producers to improve the fishmeal-free feed, including by optimising feed conversion.
Solving technical challenges
According to Feed One, eliminating fishmeal from eel feed presented three major technical hurdles.
Removing fishmeal can diminish palatability and reduce feed intake as the feed becomes less attractive to eels without the distinctive aroma of fishmeal.
Fishmeal also helps maintain the feed’s physical structure, meaning fishmeal-free formulations can be harder for eels to consume efficiently.
To address these challenges, Feed One developed a formulation combining plant proteins such as concentrated soy protein, animal proteins including chicken meal, and palatability-enhancing ingredients such as shrimp and squid meal.
The company said the formulation was designed to maintain feed attraction, support sustained consumption and preserve handling characteristics without relying on fishmeal.
Solving a technical challenge
Removing fishmeal entirely from eel feed posed several technical challenges, according to Feed One.
The company said fishmeal contributes more than just nutrition, helping to attract fish to feed, maintain feed structure and support palatability.
Without fishmeal’s characteristic aroma, eels are less likely to be attracted to feed.
The loss of fishmeal’s binding properties can also make feed difficult to handle and consume, while the absence of key sensory cues may reduce feed intake.
To overcome these hurdles, Feed One developed a formulation combining multiple protein sources and palatability-enhancing ingredients.
The feed contains plant proteins, including concentrated soy protein, alongside animal proteins such as chicken meal, which the company described as having a stable supply.
The formulation also incorporates ingredients including shrimp and squid meal to improve palatability and feed attraction.
Feed One said the combination was designed to deliver strong initial attraction, sustained feed consumption and good handling characteristics during feeding.
According to the company, overcoming these challenges enabled it to develop what it describes as the industry’s first completely fishmeal-free compound feed for eels.
