Optimising growth and physiological performance of tilapia ( Oreochromis niloticus ) in a modular multitrophic aquaculture system with natural feed integration

This study investigated the impact of alternative protein-enriched diets on the growth performance, haematological profile and biochemical parameters of Oreochromis spp. reared in a modular multitrophic aquaculture system. Four dietary treatments were evaluated: a control group (100% commercial feed) and three experimental groups supplemented with natural protein sources, including Artemia, Spirulina platensis and Hermetia illucens (black soldier fly larvae), alone or in combination. Results showed that all experimental diets significantly enhanced growth performance compared to the control (p < 0.05). The highest final body weight (301.4 ± 49.3 g), specific growth rate (5.27 ± 0.51% day−1) and lowest feed conversion ratio (1.03 ± 0.21) were recorded in group C, receiving 25% Hermetia illucens and 10% Spirulina. Haematological analyses revealed a significant increase in red blood cell count (1.98 ± 0.15 T/L), haemoglobin (Hb) concentration (88.2 ± 4.9 g/L) and mean corpuscular Hb concentration (360 ± 3.4 g/L) in fish fed the enriched diets, particularly group C (p < 0.001). Biochemical assays indicated a marked elevation in plasma total protein (59.1 ± 5.5 g/L) and creatinine levels (22.4 ± 1.9 µmol/L) in the enriched diet groups, suggesting improved metabolic and physiological status. These findings demonstrate the potential of integrating insect meal and microalgae as sustainable and effective protein sources in tilapia aquafeeds, promoting optimal health and growth within an ecologically responsible aquaculture model. The results demonstrate the feasibility of multitrophic aquaculture and natural protein alternatives.