Atlantic halibut, the largest flatfish in the Atlantic, is being farmed in Norway, Scotland and Canada. While the production has historically been modest, the Norwegian halibut industry is experiencing significant growth. Overcoming previous limitations primarily linked to larval development challenges, advancements in management strategies have facilitated more efficient production methods. Presently, the focus lies on optimizing the on-growing phase.
However, a notable knowledge gap persists regarding the nutritional requirements of Atlantic halibut. In an effort to address this, we conducted an initial assessment of water-soluble vitamin and mineral requirements.
Retention of the vitamins were analysed in liver, muscle and gills and minerals were analysed in whole fish. Requirements were estimated based on a piecewise linear regression with breakpoint .
This approach is based on the premise that once the fish’s dietary requirements for water-soluble vitamins are met, any excess will be excreted. Consequently, there exists a linear relationship between dietary and tissue vitamin levels up to this point. Beyond this threshold, tissue accumulation no longer correlates with increasing dietary levels.
For instance, thiamine requirement was estimated to be 12 mg/kg, although riboflavin estimation is uncertain due to significant variation. Pyridoxine was estimated at 6.2 mg/kg, cobalamin at 0.24 mg/kg, and pantothenic acid at 20 mg/kg. Biotin, vitamin C, and mineral results will be presented and discussed during the presentation.
This method offers the advantage of simultaneously assessing multiple nutrients in a single feeding trial, thereby minimizing the use of animals and resources. However, there is a risk of interaction effects that may influence requirement estimations.