Evaluation of black soldier fly (Hermetia illucens) larvae meal at a 5% dietary inclusion in practical diets for Nile tilapia (Oreochromis niloticus) juveniles

The rising cost of fishmeal threatens aquaculture sustainability, necessitating alternative protein sources. Black soldier fly larvae meal (BSFLM) has emerged as a promising candidate, yet evidence regarding the total substitution of minor fishmeal fraction in Nile tilapia diets remains limited. A 50-day feeding trial was conducted with 100 Nile tilapia juveniles (initial weight: 15.22 ± 7.60 g; this variance reflects a natural, unsorted batch, which was statistically accounted for by using tank means) in a closed-circuit system (RAS). For this purpose, two experimental diets were formulated with the same basal ingredients. The control diet contained 5% fishmeal, whereas in the experimental diet fishmeal was completely replaced (100%) by black soldier fly ( Hermetia illucens ) larvae meal, incorporated at the same dietary inclusion level (5%) of the total ration. Growth performance, haematological parameters, and economic efficiency were evaluated. The replacement of fishmeal with BSFLM resulted in comparable growth performance across all parameters: final body weight (FM: 43.04 ± 17.58 g; BSFLM: 45.92 ± 20.64 g), feed conversion ratio (FM: 1.018 ± 0.171; BSFLM: 1.020 ± 0.172), specific growth rate (FM: 1.83 ± 0.25%/day; BSFLM: 1.77 ± 0.16%/day), and survival rate (FM: 97.81%; BSFLM: 98.88%), with no significant differences. Haematological parameters including RBC, WBC, haemoglobin, haematocrit, MCV, MCH, and MCHC remained within normal ranges and showed no significant variation between treatments. Economic analysis revealed negligible cost differences between diets (FM: USD 0.81/kg feed; BSFLM: USD 0.82/kg feed) and the cost to produce one kilogram of fish (FM: USD 0.824/kg fish; BSFLM: USD 0.836/kg fish). The replacement of the 5% fishmeal fraction with BSFLM maintains growth performance, physiological health, and economic viability in Nile tilapia juveniles. BSFLM represents a sustainable alternative protein source for Nile tilapia aquaculture without compromising biological or economic performance in practical, low-inclusion formulations.