Substrate composition determines protein and lipid accumulation in black soldier fly larvae

The black soldier fly (BSF, Hermetia illucens) is increasingly recognized for its ability to convert organic waste into high-value biomass rich in protein and lipids. This study investigated how different substrate formulations—comprising sludge, chicken feed, and cow manure—affect the nutritional composition of BSF larvae, with implications for their economic use as a sustainable protein source and biodiesel feedstock. Seven treatments were prepared using varying proportions of sludge, chicken feed, and cow manure. BSF larvae were reared under controlled conditions for 20 days. Substrates and larvae were analyzed for physicochemical parameters including pH, electrical conductivity, nitrogen, protein, and fat content, as well as macro- and micro-nutrient profiles. Descriptive and inferential statistics, including ANOVA and chi-square tests, were performed to assess differences between treatments. Significant variations (p < .05) were found in BSF larvae composition across treatments. The highest protein content was observed in larvae fed 100% chicken feed (45.55%), followed by 100% sludge (42.47%) and 75% sludge + 25% chicken feed (41.79%). Maximum fat content was recorded in the 75% sludge + 25% chicken feed group (30.38%). Cow manure–based treatments showed the lowest protein and fat yields but increased pH and salinity levels. Cobalt was detected only in the 100% chicken feed treatment, possibly due to trace mineral additives. Substrate composition significantly influenced BSF larvae biochemical profiles. Combining sludge with nutrient-rich inputs like chicken feed enhances both protein and fat yields, supporting BSF larvae’s economic viability for feed and biodiesel industries.