Functional feed additives in aquaculture feeds

The concept of functional aquafeeds represents an evolving concept for fish and crustaceans diets. In the design of functional feeds, a wide range of feed additives can be used to extend beyond the satisfying basic nutritional requirements of the target species to improve growth and feed utilization, but also to support the health and stress resistance of the animals. The nature and characteristics of these feed additives is quite diverse, and their application into diet formulations targets a specific purpose. Some additives, such as acidifiers, exogenous enzymes, are used to improve the animals’ performance by providing enhanced digestibility of the feed materials, or counteracting the negative effects of antinutrients. Other additives, such as probiotics, prebiotics, phytogenics, and immune-stimulants target the improvement of intestinal health, stress, and disease resistance. In this chapter we focus on the performance-enhancing feed additives that are used in a new category of feeds called functional feeds.