Nutritional Assessment of a Commercial Fish Feed for Freshwater Crustacean Decapods: Implications for Multitrophic Aquaculture Systems

Integrated multi-trophic aquaculture (IMTA) enhances sustainability by optimizing feed use. Freshwater decapod crustaceans, such as aeglids and palemonids, act as nutrient recyclers and potential biomitigators in fish farming. This study evaluated the digestibility and nutritional status of Aegla uruguayana (Schimitt, 1942) and Macrobrachium borellii (Nobili, 1896) fed omnivorous fish feed for IMTA integration. Forty-five wild-caught adults of each species were weighed, measured, and housed in aquariums. They received commercial feed (PA-27, Garay-SRL®) ad libitum twice daily, with feces collected for analysis. At the trial’s end, crustaceans were weighed, measured, sacrificed, and their hepatopancreas analyzed. Aegla uruguayana efficiently digested proteins, lipids, and carbohydrates, increased biomass, maintained a normal hepatosomatic index, and showed no histological signs of dietary restriction, enabling reserve accumulation for physiological processes. These findings support its suitability for IMTA with omnivorous fish. Although M. borellii showed no significant growth, it maintained an acceptable survival and hepatopancreatic integrity, suggesting its potential as a non-fed and resilient extractive species in omnivorous fish culture. Its performance may improve when integrated with species fed high-protein feed.