Bioconversion of restaurant food waste via black soldier fly larvae into a high-value protein source for improving meat quality in finishing pigs.

Addressing the dual challenges of food waste management and sustainable protein production requires circular economy solutions. This study demonstrates a sustainable approach to convert restaurant food waste (FW) into a protein-rich feed ingredient using black soldier fly (BSF) larvae. The nutritional profile of the FW-derived BSF meal was evaluated and compared to soybean meal (SBM). BSF meal had higher digestible (20.08 MJ/kg) and metabolizable (18.74 MJ/kg) energy than SBM (P < 0.01). The standardized ileal digestibility of amino acids in BSF meal (78.90%-85.12%) was comparable to or better than that of SBM. In the subsequent experiment, 72 pigs were assigned to either a control diet (Ctrl) or an experimental diet (BSF) with 20% SBM replaced by BSF meal. Throughout the trial, the BSF group showed a 5.80% higher average daily gain (P = 0.06) and a 4.29% higher average daily feed intake (P < 0.05). BSF meal increased shoulder backfat thickness and muscle decanoic acid content by 26.68% and 83.33%, respectively (P < 0.05). Furthermore, BSF meal improved lipid metabolism and antioxidant status, as characterized by reduced serum total cholesterol and malondialdehyde levels, and up-regulation of myosin heavy chain I expression (P < 0.05). BSF meal modulated the gut microbiota by enriching taxa linked to improved meat quality and health, including Clostridium_sensu_stricto_1 (1.97-fold) and Clostridiaceae (1.94-fold) (P < 0.05). In conclusion, BSF-based bioconversion effectively transformed FW into a sustainable, high-performance feed ingredient that enhanced pig productivity and meat quality, thereby contributing to a more circular and resilient food system.