Enhancing chicken manure with bread waste and black soldier fly associated bacteria to increase larval biomass

Black soldier fly larvae (BSFL) represent a promising and sustainable source of protein and essential nutrients for poultry feed. This study aimed to improve BSFL growth and organic waste bioconversion by utilizing chicken manure (CM), a widely available but environmentally problematic byproduct of poultry production due to its unpleasant odor, greenhouse gas emissions, and pathogen risks. In the first trial, CM was combined with bread waste (BW) at different ratios to overcome the poor larval growth observed when reared on CM alone. The 1:1 BW: CM mixture yielded the highest larval biomass, feed conversion efficiency, and nutritional value. In the second trial, beneficial bacteria were isolated from BSF egg surfaces and larval guts (3.5 × 10⁶ and 2.4 × 10⁶ CFU/ml, respectively). Thirteen isolates were screened for urease and protease activity, and five were selected and identified using phenotypic traits and 16 S rRNA sequencing: Microbacterium paraoxydans, Bacillus proteolyticus, Priestia megaterium, Bacillus subtilis, and Morganella morganii. Supplementation of CM-based diets with these strains significantly improved BSFL dry weight and feed conversion efficiency, with the most notable enhancements achieved using M. paraoxydans and M. morganii. Amino acid analysis of larvae fed a 3CM:1BW diet supplemented with M. paraoxydans revealed elevated levels of essential (Isoleucine, leucine, Phenylalanine, valine) and non-essential (alanine, Glycine) amino acids. Overall, this study demonstrates a cost-effective and eco-friendly strategy for optimizing BSFL production while recycling organic waste in sustainable livestock systems.