Neither salmon, rainbow trout, cod nor halibut eat plants in the wild, while today various plant-derived ingredients are used in fish feed.

VKM was requested by the Norwegian Food Safety Authority (Mattilsynet) to assess how plant-derived ingredients in feed can fulfill the requirement in the Feed Commodity Regulation §7 of “not resulting in injury or harm to animals” (in this instance, farmed fish).

The risk assessment is based on available scientific data, documentation and literature.

In some cases, diets containing up to 20% inclusion level of high-quality plant protein sources have resulted in better nutrient digestibility and growth parameters than the fishmeal-based control diets. When substituting fishmeal with plant ingredients, however, it is necessary to balance the diets regarding limiting amino acids and minerals

Modern finfish aquaculture faces problems such as bone and skeletal deformities, cataracts, heart disorders, unspecific ulceration and various digestive disorders including intestinal colic in Atlantic cod, gastric dilatation (bloat) in rainbow trout, and intestinal tumors, at low incidence, in Atlantic salmon broodstock.

Most of the mentioned problems have been related to malnutrition, feed, intensive growth and/or unfavourable environmental conditions. The disorders are often not lethal, but may imply a fish welfare problem and increase the susceptibility to secondary disorders and infectious diseases.

Major changes in feed composition and feed ingredients may increase the risk for such production-related disorders in intensive fish farming. Care should be taken when choosing plant alternatives, both types and qualities, to prevent nutrition-related diseases such as skeletal deformities, cataracts, heart conditions, and other, unspecific symptoms.

The VKM Panel on animal feed was responsible for this risk assessment.