Black Soldier Fly (<i>Hermetia illucens</i>) Larvae for Nile Tilapia (<i>Oreochromis niloticus</i>) On-Farm Feeding: Effect on Performance and Profitability
Authors: Mathai Edwin N. , Barwani Didier K. , Mwashi Vincent , Munguti Jonathan M. , Iteba Jacob , Wekesa Francis , Tanga Chrysantus M. , Kiiru Peter , Gicheha Mathew G. , Osuga Isaac M. 
Published: September 2024

Aquaculture is one of the fastest growing sector in agriculture. However, this increase is constrained by the high cost of fish feeds occasioned by scarcity of fish meal (FM) which is a main source of dietary protein in aquafeeds. This necessitates the need to consider alternative protein sources that are sustainable, cheap, available and highly nutritious. Recent studies have shown that black soldier fly (Hermetia illucens) larvae (BSFL) and FM have a nutrient profile that is closely comparable and therefore, the fly meal is feasibly cheaper alternative to FM in making fish feeds. This study sought to find out the effect of replacing FM with BSFL meal on growth performance of Nile Tilapia (Oreochromis niloticus, L) and the corresponding profitability. The experimental diets adhered to the nutritional requirements of Nile Tilapia nutritional requirements. A total of five dietary treatments were tested. The treatments differed on the inclusion levels of BSFL meal. The experimental diets corresponded to 0% (T0; control), 25% (T25), 50% (T50), 75% (T75) and 100% (T100) group. The diets were fed to a total of 600 fingerlings. The fingerlings were assigned to 20 cages built in an earthen pond, with 30 fingerlings in each. The experimental units were randomly assigned to each of the cages. Each treatment was replicated four times. The fingerlings were fed the experimental diets for 26 weeks. The results of the current study indicate that feed intake was lowest in fish fed on diets T0 and T100. However, despite treatment T75 having the highest body weight gain compared to all other treatment diets, there was no statistical significance (p>0.05) for the body weight gain amongst the treatments. Nevertheless, there was a significant difference (p<0.05) in specific growth rate (SGR) within and between treatment diets. The SGR were 0.35, 0.41, 0.42, 0.44 and 0.52 for treatments diets T0, T100, T25, T50 and T75 respectively. Treatment diet T25 recorded the lowest feed conversion ratio (FCR) compared to the other treatments diets. Further, the results indicated that survival rates from different treatment groups in the study were significantly different (P<0.05) with the highest being recorded in T75 and T100 at 95.83% and 95.00% respectively while T0, T25 and T50 resulted to survival rates of 91.67%, 90.83% and 93.33% respectively. The increasing levels of BSFL substitution with FM resulted in a corresponding reduction in feeding costs, which yielded higher gross profit margins. Treatment group T75 realized the highest return on investment (ROI) followed by T100. The cost benefit ratio (CBR) of diet group T100 was the highest followed by T75 with the lowest being realized from T0 diet. The study found that 75% (T75) replacement of FM with BSFL meal was ideal for optimal weight gain, feed conversion ratio (FCR), specific growth rate (SGR) and conditional factor (K).