Plant based diets for farmed fish

Abstract

World aquaculture is growing (+ 8% per year) to meet the increasing demand of fish for human consumption that capture by fisheries can no longer cover. Consequently, the need for aquafeed and feedstuffs is rising while volumes of fishmeal and fish oil, the traditional aquafeed ingredients, remain stable. More and more fishmeal and fish oil are substituted by plant products. Between 80 and 95% of fish meal can be replaced by a combination of plant protein sources providing the indispensable amino acids in sufficient quantity to meet the fish needs. Beyond this substitution rate, feed intake, feed efficiency and growth rate decrease and metabolic changes are observed despite the diets containing all the required nutrients. Fish oil can be replaced by a mix of vegetable oils without deleterious effect on fish growth and health, provided that the diet supplies essential fatty acids. Fatty acids requirements vary with species according to their capacity to synthesize EPA and DHA. However, in all species, fish oil substitution results in a reduction in the flesh content of these ω3fatty acids. Research must continue to further reduce the reliance of aquaculture on fishery resources while
ensuring an efficient fish production of high quality products with limited environmental impacts.