Replacement of Fishmeal with Black Soldier Fly (Hermetia illucens L.) Larvae (BSFL) Enhances the Growth Performance of Nile Tilapia (Oreochromis niloticus L.) Fry in Tanks

Due to the rising cost and limited availability of fish meal (FM), researchers have focused on exploring alternative animal feed sources such as black soldier fly larvae (BSFL) in aquafeed industry. This study investigated the effects of replacing FM with full-fat BSFL on the growth of Nile tilapia fry at inclusion levels of 0%, 25%, 50%, 75% and 100%, hereafter designated as BSFL0%, BSFL25%, BSFL50%, BSFL75% and BSFL100% respectively. A total of 500 healthy Nile tilapia fry (mean weight =2.7±1.1 g) were randomly stocked into 10 plastic tanks (50 fry per tank; two replicates per treatment) and fed for 150 days. Fish were fed three times daily and weighted biweekly to monitor growth performance and adjust the feed offered for the fish. Water quality parameters including temperature, pH and dissolved oxygen were monitored using a real-time IoT device known as SynWater which is SYNELIXIS innovative solutions. Nile tilapia fry fed on BSFL100% showed significantly higher fish weight (74.52±1.32) compared with BSFL25% and BSFL50% (p < 0.05), but no significance difference was obtained among BSFL100%, BSFL75% (65.98±1.54) and BSFL0% (61.2±2.08). Regardless of BSFL inclusion levels, all measured water quality parameters remained within acceptable ranges for optimum Nile tilapia fry growth. A simple economic analysis showed that the BSFL100% diet significantly reduced the feed cost and increased the profit index by 52% compared with the FM control diet (BSFL0%). This study demonstrated that BSFL can fully replace FM without adversely affecting the growth of Nile tilapia or the water quality parameters. Future research should focus on optimizing BSFL production techniques in order to promote low-cost insect-based protein diets for livestock and fish production in Ethiopia.