Cargill says this shows the need for more research focused on rainbow trout.
Photo: Nofima
Nofima has participated in a research project promoted by Cargill and operated by Hofseth Aqua to thoroughly analyze the effects of different omega-3 levels in rainbow trout.
The researchers have examined how these fatty acids act through cellular mechanisms and how they influence growth, health, and fillet quality under commercial sea-cage farming conditions.
"Much of the knowledge we have on salmonids comes from research on salmon. But the species are not the same, so it is important that we obtain specific knowledge about rainbow trout," assured Marta Bou, a scientist at Nofima.
On the one hand, fish were stocked in cages at three different sites along the west coast of Norway and at different times of the year, after being fed two levels of omega-3: one standard and one elevated.
Moreover, rainbow trout and Atlantic salmon were compared at Nofima's research station in Sunndalsøra to determine whether there were differences between the two species in the absorption and metabolism of omega-3 fatty acids.
One of the main conclusions they reached was that clear differences were observed between salmon and rainbow trout, with the latter storing more omega-3 in the fillet than salmon when fed the same diet.
For example, studies indicate that providing rainbow trout with higher-than-normal levels of omega-3 does not enhance their health, survival, or offer additional advantages in aquaculture.
On the other hand, rainbow trout fed either the standard or the elevated omega-3 levels meet the daily EPA+DHA dietary requirement and also contain more omega-3 than salmon.
Nevertheless, "this does not necessarily mean that it represents an efficient overall use of resources," Bou concludes. According to Cargill, this is clear evidence that greater investment is needed in research specifically focused on rainbow trout.