Functional proteins for low fishmeal diets
Aquafeed production has passed 40 million tonnes globally, demanding an increased amount of high-quality protein. Stagnated fishmeal supplies, combined with increasing raw material prices, have stimulated the adoption of alternative plant-based and rendered ingredients. Novel protein sources such as insect meal, single cell proteins, yeast and algae are also increasing.
The most frequent negative outcomes when replacing fishmeal are decreased feed attraction and palatability, which can lead to lower feed consumption, resulting in reduced essential amino acids and energy digestibility. This can result in inferior fish performance, impaired feed efficiency, and the reduction of essential micronutrients and fatty acids.
Furthermore, alternative ingredients can carry anti-nutritional factors such as saponins, tannins, lectins, etc. These compounds are not completely inactivated or destroyed during feed processing, potentially causing acute or chronic metabolic disorders. Soybean-induced enteritis in Atlantic salmon is a well-known example of how a feed ingredient can disrupt gut health by initiating an inflammatory process.