Over 50% of global fish is provided by aquaculture whose dependency on fish meal and oil for quality aqua-feed is unsustainable due to dwindling wild fish stocks and use of small pelagic fish species traditionally predestined for fish meal as human food. Edible insects especially black soldier fly larvae (BSFL) is promoted as an alternative sustainable source of feed protein and oil for animal production including aquaculture that consumes 60% of global fish meal. However commercial production of black soldier fly larvae is still low (4%) in Uganda. Inadequate information on profitability of the enterprise based on locally generated waste substrates is placed among key limiting factors (Siva Raman et al. 2022). We evaluated the viability of producing BSFL fed on three locally generated, nutrient rich organic waste substrates; brewery waste (BW), chicken waste (CW) and potato peelings (PP) for aqua-feeds.
Objectives of the study: To determine the effect of substrate type on BSFL weight gain, proximate nutrient composition of BSFL as a fish feed protein and profit margin of producing BSFL.
Materials and methods
A cross sectional study design based on an experimental study design was used. 59,100 five-day-old black soldier fly larvae (5DOL) were divided into nine (9) groups of 3,600 BSFL each that were randomly fed on 6 kgs of three wastes/substrates; brewery waste (BW), Chicken waste (CW) and Potato peelings (PP) whose proximate nutrient analysis is presented in Figure 1.
After 16 days, 50 NSFL were randomly selected and humanely killed by blanching (instant hot water treatment) as described by (Larouche 2019). Individual weight was taken while batches were dried and analysed for proximate nutrient composition and profit margin. Data on proximate nutrient composition (%) of crude protein and crude fiber was determined following standard analytical procedures by the Association of Official Analytical Chemists (AOAC 2000); and that on profit margin (%) derived according to (Shi et al. 2021) after sale of the BSFL produced from each substrate according to Equation 1