Skretting unveils new generation of hatchery feed with better resource utilization and lower emissions

Trials show a reduction in emissions of phosphorus and zinc from feces of up to 30%, while fish fed with Nutra Terra have significantly better growth and a lower feed factor.

Credits: Skretting
December 20, 2023

Skretting introduced Nutra Terra, a novelty in hatchery feed with documented high performance and reduced emissions.

“Nutra Terra represents our largest innovation in grower feed for juvenile fish in over a decade. All available knowledge and research have been gathered to develop a new and optimized feed recipe. The result is a feed that provides better performance while reducing emissions from the fish and making better use of raw materials in the feed,” the company said.

Nutra Terra contains smaller amounts of limited raw materials such as fishmeal and phosphorus compared to conventional hatchery feeds. Part of the fishmeal is replaced with insect protein, which is part of the natural diet of salmon in the wild during this life stage.

“Validation trials show a 7% increase in growth and 4% lower feed factor in fish fed with Nutra Terra. It is gratifying to see such good performance numbers while reducing the need for limited raw materials,” said Marcus Søyland, head of land based in Skretting Norway.

Lower emissions of phosphorus and zinc and better fish welfare

The increased use of new feed raw materials and optimization of existing raw materials help ensure sustainable growth in the aquaculture industry. One of the major changes in Nutra Terra's feed prescription is the enzyme phytase, which makes phosphorus and zinc in plant raw materials more accessible to the fish. This makes it possible to reduce the total amount of phosphorus and zinc added to the feed.

“Trials show that fish absorb more phosphorus and as much zinc with Nutra Terra, even though the feed contains less of these minerals. A pleasant effect of this is that less phosphorus and zinc are excreted in the feces. In trials, we have seen that emissions of phosphorus and zinc are reduced by 30% in fish fed with Nutra Terra,” said Søyland.

Deformities are a well-known challenge in the aquaculture industry, and phosphorus plays an important role in the development of fish skeletons. “In Nutra Terra trials, we have analyzed the spine of the fish to look at mineralization and deformities. The results show that fish fed with Nutra Terra accumulate more phosphorus in the spine, which is positive for bone development,” Søyland explained.

A contribution to better sludge quality

The sludge from hatcheries can potentially be used to produce fertilizer. In order for sludge to be used as fertilizer, it must meet quality criteria set out in the fertilizer regulations. The amount of zinc is central to the grading of the sludge. Trials document that fish fed with Nutra Terra utilize zinc more efficiently, and the amount of zinc in feces is reduced.

“Reduced zinc emissions open up new and more valuable uses for the sludge from land-based production facilities. In some fjords, phosphorus emissions can limit production, and the reduction in phosphorus emissions can give our customers new opportunities for increased production,” Søyland concluded.