Plant and novel aquafeed ingredient Impact on fish performance and waste excretion

The use of fish meal alternatives in aquafeeds is becoming a necessity due to the declining fisheries stocks; thus, sustainable dietary formulations remain a big challenge for the aquaculture sector. Although plant ingredients have been successfully used as an alternative to fish meal for some aquaculture species, their anti-nutritional content often interferes with feed acceptance, digestibility, and animal performance. Besides the increased production costs, other concerns also arise from these impairing effects, such as waste production originating from nutrients not retained in biomass and released in the environment as fecal or non-fecal losses. In the search for high-quality and sustainable aquafeeds, the use of novel ingredients, such as meals from insects, yeasts, or algae, has been the focus of the aquafeeds production sector over the past few years. However, the impact of the use of such ingredients should be carefully evaluated for animal performance and digestibility. In this chapter, we address the impacts of both common plant as well as novel ingredients for use in fish performance and waste production. Reduction of waste outputs can potentially be achieved through the improvement of feed formulation, palatability, digestibility, and nutrient retention. Therefore, knowledge of the contribution of different feed ingredients and their components on fish performance and fecal properties in aquaculture is of great importance.