Evaluation of a Black Soldier Fly (Hermetia illucens) Larvae-Based Diet on the Growth Performance of the Nile Tilapia (Oreochromis niloticus l., Brazilian Strain) During Grow-Out Period in Côte d’Ivoire

Tropical aquaculture is often constrained by the high cost of imported commercial feeds. This study evaluates a locally sourced alternative by investigating the potential of black soldier fly (Hermetia illucens) larvae meal as a sustainable protein ingredient in grow-out period for the Nile tilapia (Oreochromis niloticus L., Brazilian strain). A 120-day feeding trial was conducted at Nangui ABROGOUA University using fish with an average initial weight of 120g. Three diets were assessed: a commercial reference feed and two experimental formulations incorporating agro-industrial by-products. The DBSF diet included insect meal, whereas the DNBSF diet excluded it. All diets were isoproteic (29-30% crude protein), and fish were stocked at a density of 20 individuals/m³ under uniform rearing conditions. Tilapia fed the DBSF diet exhibited growth performance (368.40 ± 8 g) and feed conversion ratios (FCR = 1.56 ± 0.07) comparable to those fed the commercial diet (379.20 ± 5.7 g; FCR = 1.49 ± 0.03). In contrast, the DNBSF diet resulted in significantly lower growth (314.40 ± 10.2 g) and feed efficiency (FCR = 1.98 ± 0.11). Peak body protein content (18%) was observed in fish receiving the reference diet. Economically, both experimental diets reduced feed costs per kilogram of weight gain by 64.69% with DBSF and 55.31% with DNBSF demonstrating their cost-effectiveness. Notably, the DBSF diet achieved the lowest production cost per kilogram of gain. These findings underscore the nutritional and economic viability of H. illucens larvae meal as a sustainable feed component, offering promising prospects for enhancing feed autonomy and reducing production costs in Ivorian aquaculture systems.