Black Soldier Fly Larval Meal as a Cost-Effective Protein Source for Enhancing Tilapia (Oreochromis niloticus) Growth

Tilapia is an important freshwater species in global aquaculture, but rising commercial feed costs have reduced its economic viability. Black Soldier Fly Larval (BSFL) meal offers a cost-effective, protein-rich alternative that can lower feed expenses and increase the profit by utilizing food waste for production. The objective of the present study was to evaluate BSFL Meal as an alternative protein source for tilapia growth and to assess its economic impact in Sri Lanka. A 42-day feeding trial was conducted using a completely randomized design to evaluate the effectiveness of BSFL meal as a protein substitute in tilapia diets. The study included four treatment groups, each conducted in duplicate, a control group fed 100% commercial feed, and three experimental groups fed diets containing 50%, 75%, and 100% BSFL based feed, respectively. Each tank was stocked with 10 tilapia fries of uniform size, with a mean initial body weight of 27 ± 2 g and a mean initial total length of 9.5 ± 0.5 cm. Fish growth performance was assessed through measurements of length, weight gain, and feed conversion ratio (FCR), while feed cost was analyzed to determine economic viability. The final average length (cm) of tilapia was recorded as 11.28±0.37, 11.40±0.59, 11.12±0.38, 11.01±0.50 in control, treatment 1, treatment 2 and treatment 3, respectively. In terms of final average weight (g) the results were 52.55±5.93, 51.20±3.68, 49.15±3.26, 45.56±2.24 in control, treatment 1, treatment 2 and treatment 3, respectively. Fish weight and length differed significantly among the feeding groups (P < 0.05), as determined by ANOVA. However, Tukey’s HSD post-hoc test revealed a statistically significant difference in weight (P < 0.05) only between the control group and the 100% BSFL group (Treatment 3). The average FCR for the control, treatment 1, treatment 2, and treatment 3 groups was 1.20 ± 0.21, 1.27 ± 0.22, 1.36 ± 0.29, and 1.46 ± 0.14, respectively. There were no statistically significant differences in FCR between the ccontrol group and any of the treatment groups. Increasing the inclusion level of BSFL meal reduced the feed cost to two-thirds of the original cost. This study concludes that BSFL meal can replace up to 75% of commercial feed without negatively impacting growth performance or feed efficiency. No significant differences were observed in key growth parameters, and feed costs were substantially reduced. Thus, BSFL meal can be used a viable, cost-effective alternative protein source in tilapia feed.