Discovery increases muscle firmness

Scientists at Nofima Ingrediens have discovered a new component in fish feed that influences muscle firmness in salmon.

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Portrettbilde av Sissel Albrektsen
Sissel Albrektsen

Senior Scientist
Phone: +47 922 89 743

By adding the amino acid hydroxyproline to fish feed, it is possible to achieve a higher level of muscle firmness, which is an important quality criterion for farmed fish.

Increased muscle firmness gives better meat quality and product properties, which can lead to increased profitability for the aquaculture industry.

Storing salmon at a low temperature in the post-slaughter period showed increased muscle firmness in fish fed with the feed containing the hydroxyproline supplement after 5.9 and 15 days of storage. When compared with the control fish, the effect was greatest after nine days’ storage.

"These measurements are quite clear. This is sensational," says Senior Researcher Sissel Albrektsen at Nofima Ingrediens.

The findings indicate that it is possible to maintain a high level of firmness in the meat in the important period from when the fish is slaughtered until it reaches the market by feeding the fish hydroxyproline. This can have major economic advantages for the aquaculture industry.


  • Increased muscle firmness
  • Stimulated collagen production
  • Increased strength in the connective tissue
  • Better meat quality and product properties
  • Better health and resistance to disease
  • Enables increased use of plant feed raw materials
  • Enables increased production and profitability

Profitable for other industries

The Nofima scientists’ findings open the opportunity for the use of hydroxyproline as a feed supplement also for animals and poultry, where optimal growth and health are also important criteria.

Hydroxyproline influences collagen production and can thereby strengthen the function of connective tissue in tissue other than muscle, such as skin, shell, bowel and bones.

A stronger and more functional connective tissue can offer greater resistance to infections and wounds, as well as better bowel habits and bone development.

Hydroxyproline as a supplement may also be beneficial as a dietary supplement for humans. The findings indicate potential to improve or cure some connective tissue-related ailments and diseases.

The Bergen Technology Transfer Office (BTO) has, in collaboration with Nofima Senior Scientists Anders Aksnes and Sissel Albrektsen patented the use of hydroxyproline in several areas. BTO is also contributing with funding and commercialisation of the technology.

The scientists are now hoping that this discovery will generate interest among feed manufacturers and other industries.

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