Reuse of spent brewer’s yeast to produce a South American freshwater prawn: effects on growth performance, amino acid profile, proximate and elemental composition, and egg development

Abstract

The availability of resources for aquafeed production is one of the main constraints that could hinder the rapid expansion of aquaculture. Our aim was to investigate the inclusion of spent brewer’s yeast as an ingredient in aquafeeds and evaluate the zootechnical performance, proximate and elemental body composition, amino acid profile, and egg development of the freshwater prawn Macrobrachium borellii. We fed juvenile prawns with three feeds: D18, D25, and D32, which represent 18%, 25%, and 32% inclusion of SBY as a partial substitute for FM, respectively, during a 75-day trial. Prawns cultivated with D18 exhibited higher growth increment (97.73 ± 7.30%), specific growth rate (0.39 ± 0.02%), and protein efficiency ratio (0.27 ± 0.04%) than other treatments. However, the total biomass produced, as well as the proximate and elemental body composition of prawns, was similar across treatments. The most abundant essential amino acids in the prawn’s body were arginine, leucine, and lysine while feeds showed good quality despite the limitations of arginine and phenylalanine. We observed successful hatching when prawns were fed with feed containing more SBY, indicating a more successful reproductive stock. Farming prawns with feeds containing different inclusion percentages of SBY is feasible. The inclusion of this raw material in high replacement percentages (up to 50%) is viable and could promote the bioeconomy by utilizing discarded local raw material instead of wild-caught resources.