Krill the brill
Major health benefits from adding krill to salmon feed
RECENT research has established that when krill is added to salmon feed it not only boosts fish welfare, but it significantly improves flesh quality. The findings are the result of a collaborative study between the Antarctic krill harvesting company Aker BioMarine and NOFIMA, the Norwegian Institute of Food, Fisheries and Aquaculture.
Both organisations have just released the results of their research which looked into the health and fillet quality of Atlantic salmon after a period of dietary krill supplementation.
The study, now published in the British Journal of Nutrition investigated the health parameters and meat quality of Atlantic salmon fed a diet where fish meal was substituted with krill meal during the finishing feeding period. Overall results reveal that krill meal improved the welfare and fillet quality of the salmon.
Dr. Turid Mørkøre of Nofima and author of the study said: “Antarctic krill meal has sparked the interest of marine researchers due to its nutritional profile. Previous studies have shown the proven effects of krill, with this study we wanted to uncover the basic mechanisms behind these effects, on farmed Atlantic salmon. The overall goal is to improve the systemic understanding of dietary krill meal effects on a biochemical, morphological and molecular level.”
Researchers picked out 800 Atlantic salmon, each weighing 2,270 grams, and randomly distributed them across eight sea cages at the LetSea feed trial unit in Norway. The study experimented with supplementing krill meal (12 per cent ) in a low fish meal diet (5 per cent ) among salmon. All feeds were designed to meet the nutritional requirements of salmonoid fish, with balanced EPA and DHA content. After 10-weeks, the fish were bulk weighed, and 20 fish from each sea cage were randomly selected for analysis.
Antarctic krill meal is considered to be one of the few truly sustainable marine sources of protein for aqua feeds. With a nutritional profile consisting of proteins, amino acids and ash contents, it serves as a viable alternative to fish meal. Due to this, krill has garnered interest from the research community, who seek to understand how the krill’s high levels of EPA and DHA, phospholipids, vitamins, nucleotides and natural astaxanthin impact fish health and welfare when supplemented in diets.
Overall, the study revealed positive effects on salmon health. Key findings include specific improvements in:
• Body shape – krill meal inclusion led to more voluminous body shape and higher condition factor
• Heart health – krill meal inclusion led to
reduced fat accumulation around the heart
• Fillet quality – krill meal inclusion led to a more ordered and stable collagen architecture and better muscle integrity
• Immune genes – krill meal inclusion resulted in a boosted expression of immune genes in liver, including enhanced liver coloration and increasingly responsive structural genes
• Hindgut – krill meal inclusion led to less inflammation in the hindgut and zero mucus presence.
“We knew that nourishing salmon with krill supplemented diets benefits salmon performance, overall health and fillet quality. With these new findings, we now also understand why,” says Dr. Tibiabin Benitez-Santana, Fish Nutrition R&D Director at Aker BioMarine. Dr Benitez-Santana added: “This study is an important step in fish diet and welfare research.
Krill represents the single largest marine biomass on Earth. That, coupled with its powerful nutritional value as shown in this study, as well as the sustainable methods of harvesting, make Antarctic krill meal a natural contender as a supplement in low fish meal diets.”
The British Journal of Nutrition says in the introduction to its report: “There is an urgent need to find alternative feed resources that can further substitute fishmeal in Atlantic salmon diets without compromising health and food quality, in particular during the finishing feeding period when the feed demand is highest and flesh quality effects are most significant.”
Aker BioMarine was created because of a strong belief in the positive health effects of krill. The company says: “More than a decade later, our business continues to grow because we take care of the ecosystem we harvest in. To us, it makes no sense to take something out of the ocean to improve our health, if it simultaneously compromises the health of the ocean. Ensuring the well-being of the krill biomass and contributing towards a thriving Antarctic ecosystem are among our core priorities.”
Aker BioMarine was also the first krill fishery to the receive the Marine Stewardship Council (MSC) prized eco label.
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There is an urgent need to find alternative feed resources that can further substitute fishmeal in Atlantic salmon diets without compromising health quality” and food