Evaluation of crustaceans as candidates for co-cultivation with omnivorous fish: growth, nutrition and body composition of three native decapods fed with commercial fish feed

Residual feed is a major contributor to environmental deterioration in aquaculture systems, with approximately 5–30% of the feed offered remaining uneaten. Co-culturing crustaceans with fish may help mitigate feed waste, enhance profitability, and promote sustainability. This study evaluated the zootechnical performance, nutritional status, and body composition of three decapods—Macrobrachium borellii Nobili, 1896; Aegla uruguayana Schmitt, 1942; and Trichodactylus borellianus Nobili, 1896—fed a commercial omnivorous fish diet over an 83-day period. Growth performance, survival, body composition, and hepatopancreas histology and index were analyzed. The results revealed contrasting species-specific responses. Prawns exhibited minimal growth but high survival rates; aeglids showed consistent growth and survival without histological alterations in the hepatopancreas; whereas crabs achieved the highest growth but experienced low survival, likely associated with dietary deficiencies and cannibalistic behavior. Body composition differed among species, reflecting distinct metabolic strategies and nutrient utilization of the commercial diet. Among the three species, A. uruguayana demonstrated the most favorable performance, supporting its potential as a candidate to consume residual feed in integrated multi-trophic aquaculture systems, where fish are the primary cultured species. These findings contribute new knowledge about the biology and aquaculture potential of South American crustaceans, highlighting opportunities for diversification and sustainability in agro-aquatic production systems.