Study shows krill can supply key element in salmon feed

Farmed Atlantic salmon can meet their needs for choline, an important nutrient for growth and intestinal health, when fed on a diet containing Antarctic krill, a study has found.

Researchers at the Faculty of Veterinary Medicine at the Norwegian University of Life Sciences, and krill producer Aker BioMarine, found that krill meal and krill oil supply the choline that salmon need for health and growth. Choline can also help alleviate intestinal steatosis, a condition in which lipids (fatty matter) build up in the intestine.

Krill is a small marine invertebrate (zooplankton) which can be found in very large numbers, particularly in the seas around the Antarctic region.

The 56-day feeding trial was conducted on-site at the Centre for Fish Research at the Norwegian University of Life Sciences campus in Ås, Norway. This study marks the first time that the unique choline type found in krill, called phosphatidylcholine, was evaluated for its effect on reducing intestinal steatosis in salmon. The krill ingredients for the study were provided by Aker BioMarine, from the QRILL™ Aqua product line.

During the trial, a total of six different diets were formulated, including a reference diet with no choline supplement, two diets with krill oil and another two with krill meal, each at varying levels. The sixth diet was supplemented with inorganic form of  choline, choline chloride, at a high level.

The study showed the high and similar ability of both krill meal and krill oil to reduce lipid accumulation in the salmon intestine, thus reducing the likelihood of intestinal steatosis and/or lipid malabsorption syndrome (LMS).

In a similar way, choline at lower inclusion levels from both krill meal and krill oil reduced lipid accumulation in the salmon liver to the same extent as the positive control group.

The krill meal and krill oil diets showed a growth stimulating effect in comparison to highly choline deficient diets.

Salmon growth was significantly higher in the krill meal and krill oil groups consuming 2.6g/kg of choline, in comparison to the positive control group, indicating that even sub-optimal levels of choline can satisfy choline needs for growth.

Sigve Nordrum, EVP Animal Health and Nutrition, Aker BioMarine, said: “What we learned from this study is that choline from krill meal and krill oil is equally effective, even at lower inclusion levels, in stimulating growth in fish and in supporting better intestinal and liver health. Our findings prove that krill is a functional ingredient that can significantly improve the nutritional quality of the dietary feed, leading to better quality products.”