Aquaculture feeds produced with Amazon by-products in accordance with organic certification standards: effect on growth and health of Colossoma macropomum

This study evaluated the effects of organic diets formulated with Amazonian by-products on the productive parameters and health of juvenile tambaqui (Colossoma macropomum). Four experimental diets were tested: CL (Cassava Manihot esculenta leaf meal), BN (defatted Brazil Bertholletia excelsa nut meal), CLBN (a combination of CL and BN), and FFBN (fish residue meal, black soldier fly larvae Hermetia illucens meal, and BN). A total of 180 fish (14.37 ± 0.50 g) were distributed across 12 tanks (400 L) and fed for 60 days in a semi-closed system. Growth performance, body composition, metabolic, and immune parameters were assessed. Fish fed the BN diet exhibited superior weight gain (+35.34%), specific growth rate (+15.73%), and protein (+20.80%) and energy (+23.02%) retention compared to the CL diet (p < 0.05). The inclusion of 400 g/kg of cassava leaf meal reduced intestinal trypsin activity by 66%, negatively impacting feed conversion efficiency (CL: 1.41 vs. BN: 1.18). While the FFBN diet supported growth, it increased visceral fat and triglyceride levels. The CLBN diet negatively affected the immune response. Results suggest that the BN diet is the most suitable for organic production, promoting better growth and economic return without altering metabolic conditions, body composition, or tambaqui health. The use of Amazonian by-products in organic feed presents a sustainable alternative, fostering the integration of family-based aquaculture into the circular bioeconomy of the Amazon region.