A new study, conducted in collaboration with Professor Åshild Krogdahl and Associate Professor Trond Kortner at the Faculty of Veterinary Medicine at the Norwegian University of Life Sciences and Aker BioMarine, concludes that krill meal and krill oil fulfill the dietary choline needs for growth in farmed Atlantic salmon.
Antarctic krill in both its meal and oil forms is a natural and sustainable source of several important nutrients for fish, including phospholipids, omega-3 fatty acids, astaxanthin and choline. The researchers behind this study set out to evaluate whether choline from krill meal or krill oil as part of the dietary feed could help alleviate intestinal steatosis, called lipid malabsorption syndrome (LMS) in severe cases.
|Why do fish need choline?
• Choline is an essential nutrient for both humans and animals and is typically obtained through the diet.
• It supports healthy liver, brain, and muscle function, and it is important for cell integrity as well as the transport of fat in the body.
• When fish have a choline deficiency, too much fat builds up in the intestines rather than being transported and absorbed. This can be harmful to the fish growth and health.
|What is lipid malabsorption syndrome (LMS) and how does it affect fish?
• LMS is a severe condition that occurs when choline levels are too low in the fish.
• It results in a buildup of fats or lipids in intestine.
• Excessive fatty deposits in the intestine or liver of the fish can harm the fish health and reduce its overall quality as a consumer product.
“Choline is an important nutrient that is necessary for health and growth in fish. It also influences intestinal health. In our research with the Norwegian University of Life Sciences, we, tested whether choline from krill could reduce the buildup of excessive lipids in the intestine, causing LMS, which is detrimental to fish health and growth,” says Dr. Kiranpreet Kaur, Director R&D Fish Health and Nutrition, Aker BioMarine, and a corresponding author of this study.
Researchers set up an 8-week trial with Atlantic salmon, testing six different diets. The 56-day feeding trial was conducted on-site at the Center 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 full study can be found here: https://www.hindawi.com/journals/are/2023/4001633/
The study showed the high and similar ability of both krill meal and krill oil to reduce lipid (fat) accumulation in the salmon intestine, thus reducing the likelihood of intestinal steatosis and/or lipid malabsorption syndrome.
In a similar way, choline at lower inclusion levels from both krill meal and krill oil reduced lipid (fat) 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.
“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,” says Sigve Nordrum, EVP Animal Health and Nutrition, Aker BioMarine. “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.”