The key to spotless fillets?

The trial supports earlier research which suggests that incorporating krill in the feed will enhance the quality of the fish at slaughter.

These findings are contained in a brand-new Nofima report in which 200 fish were examined by Turid Mørkøre and her team at Nofima. The full-scale feeding trial was conducted at BioMar's trial license, off Senja, using salmon that were transferred to seawater in the spring of 2014. The test feed used in the trial was Qardio, which contains krill (produced by Aker BioMarine). Other trials have also shown that Qardio can reduce dark spots (melanin), as well as enhancing fillet quality, reducing inflammation and boosting HSMI resistance.

"Significant attention is currently being devoted to the occurrence of dark spots in salmon fillets, both by the industry and by specialist institutions," says Gunnar Molland, BioMar's Product Manager for Fish Health. "The melanin discolourations are assumed to be the product of a permanent inflammation process and we have also found repeated indications that feed components which modulate inflammation help to reduce the development of spots. In addition to the role played by specific vitamins and minerals we have also seen the effects of the fatty acid balance. As a consequence, it did not come as any great surprise to find that Qardio, which was already known to reduce the harmful effects of virus infections on the heart, has now also been shown to reduce the occurrence of dark spots in the fillet. The discovery that the same virus (PRV) that causes HSMI is found in dark spots in fish fillets suggests that the virus may also play a role in this context."

"Dark spots in fillets are a problem with which many fish farmers will be all too familiar," continues Molland. "This development work is being conducted by BioMar R&D and involves joint venture projects with customers and external communities of expertise. BioMar will apply the new knowledge generated in this work in the development of tools for the industry, our aim being to launch a product designed to promote cost-effective prevention of fillet spots early next year. It is also important to note that operational stress appears to be a significant factor in the development of dark spots."