In the pink

Study reveals a pigmentation breakthrough in salmon smolts

Many Atlantic salmon producers around the world have extended the period that juveniles spend in the freshwater phase of grow performance and health in sea pens.

Consequently, the reduced time that the smolts spend in seawater before harvest, allied to the generally faster growth rates being achieved in salmon production today, have contributed to a steady decline in the pigmentation period.

The pigment in salmonids that provides their prized pink colour is the carotenoid astaxanthin. Obtained naturally from plankton, algae and crustacean shells, as well as in nature-identical synthesised form, astaxanthin is also an antioxidant and a precursor to vitamin A.

Natural sources of the pigment can also be obtained from yeast and bacteria.These naturally derived sources of astaxanthin make up the majority of pigment used in the UK market.

While salmon in the seawater stage of production have always been given pigmented feeds, standard practice has been to not provide it in

Longstanding regulations relating to feed additives also stipulated months of their life.While this rule was recently lifted in the EU*, it currently remains in place in Norway.

Whereas 10 to 15 years ago it was not unusual for salmon farmers to put 40g smolt into seawater sea pens, today the tendency is for the smolt being transferred to be considerably larger and much further along in the growth cycle.

‘With the sea production time now several months shorter, the salmon Leo Nankervis, team leader of salmonid nutrition at Skretting Aquaculture Research Centre (ARC).

‘Year-on-year, we have seen pigmentation decline in various markets,

To overcome this particular pigment challenge, and following extensive containing astaxanthin, enabling pigmentation to begin prior to transfer.

‘These feeds give salmon farmers the opportunity to get a head start on the pigmentation process, which can give in excess of 0.5ppm extra