Effects of Replacement of Fish Oil with Black Soldier Fly (Hermitia illucens) Oil on the Growth Performance and Biochemical Composition of the Flesh of Nile Tilapia (Oreochromis niloticus) Fry

The black soldier fly (Hermetia illucens) is a promising insect species for use in aquaculture feeds due to its high protein and fat content, with a fatty acid profile primarily consisting of saturated and medium-chain fatty acids. In this experiment, fish oil was replaced with black soldier fly (BSF) oil in varying proportions to evaluate its effect on the growth and biochemical composition of Nile tilapia flesh. Three experimental diets designated R1, R2, and R3 were formulated, replacing 50% and 100% of fish oil with BSF oil. The best results in terms of growth performance and feed efficiency were observed with the R2 diet (50% fish oil replacement), which yielded the following average values: final mean weight (0.42 ± 0.05 g), absolute mean weight gain (0.34 ± 0.05 g), specific growth rate (4.14 ± 0.31%/day), feed conversion rate (2.45 ± 0.74), and protein efficiency coefficient (1.07 ± 0.15). Regarding the biochemical composition of the flesh, there were no significant differences in protein and ash content across the experimental diets, with the following respective values: 17.89 ± 1.49%, 17.29 ± 1.81%, and 16.78 ± 1.83% for protein, and 5.30 ± 0.39%, 4.99 ± 0.47%, and 4.59 ± 0.59% for ash content in diets R1, R2, and R3. However, a significant difference in lipid content was observed between the R2 diet and the R1 and R3 diets, with values of 4.85 ± 0.74, 3.44 ± 1.42, and 3.14 ± 1.27, respectively.