Microalgae as Fishmeal Replacements in Rainbow Trout: Effects on Growth, Feed Use and Nutrient Excretion

Abstract

The increasing need for sustainable aquaculture practices has driven the exploration of microalgae as a potential substitute for fishmeal in Oncorhynchus mykiss (rainbow trout) diets. This study evaluates the impact of microalgae-based diets on growth performance, feed conversion efficiency, and nutrient excretion in Oncorhynchus mykiss. Microalgae, rich in proteins, essential fatty acids, and minerals, offer a promising alternative to traditional fishmeal, with potential benefits in enhancing growth rates, improving feed efficiency, and reducing nutrient excretion. The results suggest that microalgae can match or exceed the growth performance of fishmeal-based diets while reducing nitrogen and phosphorus excretion, thus offering environmental advantages. Figs. 1 and 2 illustrate the comparative nutritional profiles of fishmeal and microalgae, as well as the effects of microalgae on growth and feed conversion in trout. Despite the promising results, challenges such as the high cost of production and the need for species-specific adjustments in diet formulation persist. Future research should focus on optimizing microalgae inclusion levels, improving cost-effective production methods, and conducting long-term studies to evaluate their broader ecological and economic impacts in aquaculture.